Thursday, January 31, 2008

1. Nikon Flash - Two Separate Metering Systems



After several years of using the SB800 with my Nikon D200 while shooting weddings and events, and after writing numerous posts about this on the Nikonians Speedlight Forum , I decided to consolodate my thoughts in this blog.

Note: I use the term TTL to mean the same thing as iTTL throughout this blog.

Look at the two pictures above. Notice that the first one appears as though the subject is in a cave. The background is black. But the second one has noticeable detail in the background. This blog post is about being able to adjust between these two extremes at will.

Flash photography is a pretty complex subject, and you have to study it a while to understand it. It is also a very rewarding subject and leads to much better pictures in many situations.

The first concept to wrap your head around is that when you take a flash picture it is actually a combination of two exposures; one from available light (also called ambient) and the other from flash. Already you may be able to see intuitively that flash photography will be easier in the dark, because the contribution from ambient is zero! This concept is critical to understand.

And, it is also probably intuitive that if the ambient light is bright, things can get a lot more difficult as you try to balance the two contributions to the image.

So, Nikon made things much easier for us by developing their camera and flash metering systems - these are two completely separate systems that are used together or separately, depending on how we set up our camera/flash.

So let's look at the simplest situation first; a dim room where there is only a little ambient light; like what you would find in a typical indoor home setting at night. If you take a picture in such a setting without flash, in one of the auto modes, say A mode, a typical aperture/shutter would be about f/4 and 1/4th sec at ISO 100.

Now, put the camera in manual mode and increase the shutter to 1/80th sec and leave the aperture at f/4 and shoot another shot. The picture will be very very dark - to the point that the image is barely discernable.

Now, turn on the flash in TTL mode and shoot that same shot, leaving the shutter at 1/80th and the aperture at f/4 (still in camera manual mode). You will see that whatever is in the center of the frame will be properly exposed by the flash. This is because the flash metering system handled the exposure and added just the right amount of flash power to get a proper exposure. It still may not be exactly the right exposure for other reasons, but I'll discuss that in a future blog entry.

Now, place a subject (a person is perfect for this) relatively close to the camera (say 5 feet) with a background behind the subject (say about 15 feet away), still in typical home indoor lighting. Make sure the subject is in the center of the frame and shoot a flash shot in straight TTL (not TTL-BL) leaving the camera settings at f/4 and 1/80th sec. You will find that again the subject came out properly exposed, because the flash metering system handled the exposure. But the interesting thing is that the background behind the subject is back to being very dark, just like in the shot without flash. This is because the flash power decreases very quickly from the distance of the subject to the background and it barely brightens the background at all.

Now, decrease the shutter speed to 1/10th sec and shoot again. The background will be brighter, but the subject will be the same brightness as before. Also, the subject will be sharp, but the background may also show some motion blur, because 1/10th sec is too slow to hold the camera perfectly still (unless you use a tripod). Since the flash was primary on the subject; ie, the ambient was overpowered by the flash, and the flash duration is normally faster than 1/1000 sec, the subject will be sharp with no motion blur.

This shows you that in a dim room, the flash exposure of the subject is controlled by the flash metering system and the background exposure is controlled by the settings on the camera. You can adjust them separately! This is the key behind using the flash in TTL mode and the camera in Manual mode.

Even when the ambient lighting is a little brighter than this, you can still use this technique if you stop down the camera aperture enough to make the flash the primary light on the subject, which takes the ambient light out of the equation. But then your background becomes dark. And if you try to brighten it by decreasing the shutter speed, then the bright ambient light will begin to affect the subject brightness too, and you begin to risk overexposure of the subject. In this situation, shutter, aperture, and flash power all affect the brightness of the subject. It's usually best to simply live with a dark background in this situation and make sure the flash is primary on the subject.

Now, if you are in bright ambient light (like outdoor in daylight), it is simply too bright to be able to take the ambient out of the equation by stopping down the camera, so now you have to balance the flash and the ambient. If the flash contribution to the shot will be less than the ambient contribution, then it is called Fill Flash. When there is a lot of ambient, the background and subject are no longer able to be adjusted independently, and camera manual mode becomes difficult to use. This is when you want to switch the flash to TTL-BL and the camera to one of the automatic modes (S, A, or P). The camera will then measure the ambient light to set its aperture and shutter and send this information to the flash, after which the flash metering system will set the power of the flash to make the subject the same brightness as the background.

If the ambient is extremely bright, like direct sunlight, then it's usually best to select P or S mode (and TTL-BL), so the aperture will automatically stop down to avoid overexposure. In A mode, the shutter will increase to reduce the exposure, but it will be limited by the flash sync speed of 1/250th (D200) and that is often not high enough for bright light if a wide aperture is selected.

One caviat for TTL-BL: the subject must be darker than the background for TTL-BL to work properly. The flash can only brighten the subject to balance it with the background; it can't make the subject darker. If the subject is brighter than the background to begin with, then you probably are best off not using flash. However, there can sometimes be slight shadows on the subjects face that can be 'lifted' with a very slight amount of flash in TTL mode.

Go to next post

302 comments:

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George said...

Thank you very much. If I understood correctly it is better to use 1/320 because than there is no change till 1/250 and from 1/320 and shorter and it is a little bit better than FP between 1/250 and 1/320.
Right??

Thank you so much.
Why are you in such a friendly way?
You are helping me and you did it to a lot of other people too. Without earning some money.

thanks a lot. you are great!!

Greedings, George

George said...

Hi Russ!

thanks again a lot.

So did I understand correctly?
There is no disadvantage to take 1/320.
Because till 1/250 it's the same between 1/250 and 1/320 with the setup 1/320 FP is stronger and for shorter times it is still the same again.

So I hope I did understand.
Why are you that helpful?
I think it's really great to get these support. But you don't get anything. So why are you doing this?
thank you very much.

Russ MacDonald said...

Hi George,

Yes, you have it right.

I don't have to make that choice, however, since my D3 has only 1/250th FP Sync.

Russ

George said...

again thank you so much.

Anonymous said...

Love the blog. I am devouring all the information it contains. Thank you for your insight. I am completely scared of my SB600. I am trying to understand it (emphasis on trying). I do have a question. I shoot in manual mode most of the time. If not manual, I do shutter priority for sports and Aperture priority for DOF. So when I attach the SB600 (set to TTL) in manual mode, I look in the viewfinder and the meter (I call them the popsicle stick) shows WAY WAY underexposure. It is telling me I need a greater than 1 sec. exposure (Indoors in FL on a sunny day with a bay window and sliding glass doors 4 feet away). I know this is not correct. How can I make sure I have the proper exposure. It seems my camera does not even know that the flash is attached. I took several shots increasing the shutter speed each time until I got an exposure that looked correct. I could only get the shutter speed to 200. It locked up after that. Please help me know how to use this flash in manual mode. I so so so don't wont to revert to using auto. I want to conquer this.
Sincerely,
Flashphobia in FL

Russ MacDonald said...

Hi Flashphobia,

What you are seeing is correct! That's exactly how the camera and flash work.

This happens because there are two exposure systems that don't talk to each other when in regular TTL mode. In fact, that's what this blog is all about.

The light meter in the camera doesn't know anything about the flash, and the metering system in the flash doesn't know anything about the camera settings.

Like the title of this blog says, there are "Two Separate Metering Systems".

The light meter in the camera measures only the ambient light, and the flash metering system measures only the flash.

To take a good flash picture using regular TTL, you should always underexpose the ambient by at least two stops. In other words, the meter in the camera should show underexposure by at least two stops. I think that is exactly what you are seeing. This is the amount of ambient contribution that is being made to the exposure.

The flash metering system reads the reflected energy from the preflash and sets the main flash pulse to light the subject to 'standard' brightness. So, the flash figures out how much power is needed to make the flash portion of the exposure.

When using Aperture Priority or P mode, the camera limits the shutter to 1/60th sec to help make sure you don't let too much ambient into the exposure. Of course, if you use camera Manual mode, you can set the shutter to whatever speed you want. That's when you can really mess up if you forget to underexpose by at least two stops.

The reason you should underexpose by two stops is that the flash calculates its exposure based on zero ambient. In other words, the flash doesn't take the ambient into account and it sets its power as if it were in a pitch dark room. If you keep the ambient portion down 2 or 3 stops, the ambient won't add much brightness to the exposure. If you set the camera to make a normal ambient exposure, it will add to the flash and you will get severe overexposure.

I recommend you go back now and read this blog over again. It will probably make more sense.

Hope that helps,

Russ

Juan said...

Hi from Mexico Russel!!

I´ve using TTL for a while and as almost everybody in this blog, my results have been very unconsistent and frustrating. I´d rather use my speed lights in manual mode and my sekonic meter.

But once I found your blog is like an oasis in a desert!! Really!

I can´t understand why Nikon has such a poor info about TTL. They should hire you as an Advisor!

Well then, Let´s get started with mi TTL comments:

First, I don´t want to make comparisons about who is better than who or who is right or wrong, but what I just saw in a video tutotial last week named TAMING TTL WITH WILL CROCKETT (in Friday Photo School dot com) differs in some terms from what I read in this blog:

The video assures (in my understanding) that:

1.Never use Matrix and Center weight metering. Use only Spot metering. TTL BL simple does not work.(question answered to one of the attendees).
2.By default, flash output is metered on center weighted basis (as you said in one of your post) but you can use and move the focus points among the frame (so you don´t have to recompose the scene) and the TTL system will meter the light reflected from that focus point.
3.TTL system is different (quality talking) depending of the make and model. (seem obvius for the make, but how do I know TTL from a D3 is better than D200 and likewise D200 TTL is better than the D80? I know there will be technologican improvements from one model to another, but it shouldn´t be some kind of Standard quality among the brand?
4.Also this tutorial states that if you don´t have a prime lens you will have poor readings (both ambient and flash metering).(Seems obvius too, but I have 18-200 VR nikkor lens. Is not a prime but neather a trash lens (IMO). Is this enough to have bad results?.

Your comments will be appreciated!!

Regards!!

Juan

Russ MacDonald said...

Hi Juan,

I know Will Crockett quite well, and I didn't think any of his information contradicts mine. Let's dig into it.

"1.Never use Matrix and Center weight metering. Use only Spot metering. TTL BL simple does not work.(question answered to one of the attendees)."

Well, first, the metering mode will not affect regular TTL mode. The only thing that the metering affects when using regular TTL is the ambient portion of the exposure, and only then if you are using one of the auto exposure modes (AS or P). If you are using camera Manual mode, and regular TTL, the camera meter has absolutely no affect on either the flash or the exposure.

In TTL-BL mode, the metering mode does affect the flash. In fact, in Spot metering TTL-BL is disallowed. TTL-BL works best when you put the camera in Matrix mode.

You have to fully understand TTL-BL before you can use it effectively. Many Pros do not use TTL-BL, because they don't understand exactly what it does, and they do not like the camera figuring out the flash power for you. I think Will prefers regular TTL, but I do not know if he ever has studied TTL-BL.

TTL-BL works extremely well when the ambient light is bright. It does not work well when the ambient is dim. In other words, when you want fill flash use TTL-BL when you want the flash to be primary, use regular TTL.

"2.By default, flash output is metered on center weighted basis (as you said in one of your post) but you can use and move the focus points among the frame (so you don´t have to recompose the scene) and the TTL system will meter the light reflected from that focus point."

This is not true. I have tested and proven that the focus points do not affect TTL flash power.

"3.TTL system is different (quality talking) depending of the make and model. (seem obvius for the make, but how do I know TTL from a D3 is better than D200 and likewise D200 TTL is better than the D80? I know there will be technologican improvements from one model to another, but it shouldn´t be some kind of Standard quality among the brand?"

TTL-BL has been improved on each new model, but regular TTL has remained exactly the same since the D2 and D200. The newest versions of TTL-BL now deal fairly well with dim ambient conditions and allow the flash to be primary fairly well. Regular TTL is still better, but TTL-BL is gaining. Nikon's goal is to make TTL-BL a general purpose mode that will work in all situations, but they are not there yet.

"4.Also this tutorial states that if you don´t have a prime lens you will have poor readings (both ambient and flash metering).(Seems obvius too, but I have 18-200 VR nikkor lens. Is not a prime but neather a trash lens (IMO). Is this enough to have bad results?."

I have never heard this comment before, but it does make some sense in a way. A prime lens will probably have a very wide aperture (f/1.4 or wider, maybe), and the metering always takes place with the the lens wide open. This means that you should get slightly better metering with a fast lens than a slow lens. The monnitor preflashes will register better and be easier to measure with a fast lens. But there really is no reason it has to be a prime lens. A pro f/2.8 zoom will meter just as well as an f/2.8 prime. I get superb metering with my Nikon 24-70mm f/2.8 pro lens. My Nikon 50mm f/1.4 lens also has superb metering, but I can't see any difference between it and my pro zoom. I'm not sure what this statement is trying to get to, but I think you may have missed the point a bit.

Russ

Paul said...

Very useful, and straightforward post! Thank you very much, sir! I'm just beginning using a flash (SB-600) and I was wondering about metering with it, since I'm not a fan of any "AUTO" mode (shoot fully manual all the time). This post make things very clear, and it's a good starting point

Russ MacDonald said...

Hi Paul,

Thanks for the great feedback!

I'm glad you find my post useful!

Russ

Marty said...

Russ,
It may have been mentioned to you before on these comment threads... but have you ever considered bringing all of these wonderful writings together into a book? I've read many books on photography and most of them just gloss over the detailed stuff that you do so well. This is the content that the serious photographer needs to know and is generally so difficult to find in well-written and accessible language. As for the atrocious Nikon manuals... well they should employ you to re-write them. They're very poorly written - obviously written by technicians and not photographers!

Keep up this great work Russ. It's a masterpiece in the making, for publication on paper some day I hope.

marty

Russ MacDonald said...

Hi Marty,

Thanks for the very nice feedback.

Yes, lots of people have said I should pull all this together into a book, but that would be way too much like work! I do this for fun and to help everyone be the best flash photographer they can.

I also realize I have some special knowledge that others do not have, and that the Nikon manuals were written mostly by people who did not have a strong knowledge of how the CLS technology really works. I don't think the design engineers of the flash ever even reviewed the manuals.

Thanks again for the great feedback!

Russ

Anonymous said...

Thank you Sir, for the very useful blog. I've made this my point of reference whenever I'm lost in confusion.

Russ MacDonald said...

To Anonymous (I wish you would sign your name),

Thanks for the kind feedback!

Russ

Angela2932 said...

I SO appreciate all the work you put into this, and after 2 1/2 years of trying to learn my SB800, I finally feel a glimmer of hope, after reading your excellent writing!

I can understand your not wanting to write a book, and the "work" aspect. But have you ever thought about putting this into an ebook, like through lulu.com?

You could be more "casual" about it than a major publishing effort, but your work would be preserved. . . and then would be so accessible to ereaders, even if just read on the computer. You might even make a little bit of money, enough for a lens or two!

My understanding is that people often sell their "ebooks" for $13.99 or so, with you makikng about $10; I would definitely purchase an ebook from you for such a price!

(I don't have anything to do with lulu.com--just so appreciating your excellent work!)

Russ MacDonald said...

Hi Angela,

Thanks very much for your kind and encouraging feedback.

The real issue with writing a book or an ebook is that you lock the information down. You may not realize it, but as I get feedback, I am constantly tweeking and updating my blogs.

Just last week, I learned that the regular TTL system works differently with the newer cameras than it did with my D200 that I wrote all of my early blogs about. So, I updated my blog to show the new information.

The other thing about writing the blog is that I don't have to get releases from all the subjects used. If anyone complains (no one has ever complained), I will just remove him/her and replace with someone else. Many times I use subjects that I have shot during receptions, or bridal sessions, and even though I always work under contract, and I retain all copyrights, and there is a clause in the contracts that allows me to use the pictures for advertising my business, I don't think publishing to an ebook is covered.

That would mean that I would have to hire models and reshoot all the examples I have used.

But thanks for the encouragement!

Russ

Frank said...

Hi Russ

I now get up one hour earlier every day to read your posts before going to work... Its a fantastic resource!

However it also generates som questions.

Heres a couple:

In an answer to "Bubble" from march 26, you wrote:


"So, in the case that you described, where you changed the shutter from 1/30th to 1/60th, the flash contribution to the image won't change, but the ambient contribution will increase by one stop".

The ambient contribution will increase? I dont get this. Maybe I read it the wrong way, but shouldnt it be the opposite?

Also in the same answer, you wrote:

"...When the ambient light is bright enough to significantly affect the subject, then changes of shutter speed will change the brightness of the subject as well as the background. The background will still be affected more than the subject".

and

"When I run into this situation, I simply increase the flash power to overpower the ambient, so all the assumptions will work again".

and

"This situation normally only causes a problem outdoors in daylight conditions. Then, the daylight is so bright that you cannot increase the flash enough to overpower it, and you have to use a 'fill' flash concept. It is very rare when shooting indoor flash that you cannot increase the flash power sufficiently to overpower the ambient, so that you can once again control the background and subject independently".

My question:

I am a bit confused about the concept of "overpowering the ambient".

In my understanding (and it may verywell be wrong), you "overpower" the ambient by use of a fast shutter. Isn't this what it is all about - turning background or subject dark by using a fast shutter, and after that you can control the brightness of the subject, by using your flash?

Hope you have the time to clarify this for me.

Thanks!

Frank

Russ MacDonald said...

Hi Frank,

You are correct. When you increase the shutter from 1/30th to 1/60th the ambient contribution will DECREASE by one stop. That was an error in my earlier reply (and I said it twice!). 1/30th and 1/60th need to be swapped. I wish there were some way to edit my reply, but all I can do is delete it. I may do that.

Your understanding on overpowering the ambient is correct. My wording was very poor in this reply. When I say you "increase the flash power to overpower the ambient" I meant that you increase the flash power RELATIVE TO THE AMBIENT. Of course that is done by reducing the ambient rather than actually increasing the flash.

You can also 'overpower the ambient' by closing down the aperture. When you do this the ambient contribution is obviously decreased, but the TTL system will also automatically increase the flash power to keep the subject at the same brightness. This will darken the background, but it has a side effect of increasing the depth of field at the same time.

Using the shutter to control the ambient is usually a better choice, because it will darken the ambient contribution without any side effects, and you don't risk running out of flash power like with the aperture.

Hope that helps,

Russ

Frank said...

Hi Russ

I now get up one hour earlier every day to be able to read your posts before going to work... Its a fantastic resource!

However it also generates som questions from my side.

Heres a couple:

In an answer to "Bubble" from march 26, you wrote:


"So, in the case that you described, where you changed the shutter from 1/30th to 1/60th, the flash contribution to the image won't change, but the ambient contribution will increase by one stop".

The ambient contribution will increase? I dont get this. Maybe I read it the wrong way, but shouldnt it be the opposite?

Also, in the same answer, you wrote:

"...When the ambient light is bright enough to significantly affect the subject, then changes of shutter speed will change the brightness of the subject as well as the background. The background will still be affected more than the subject".

and

"When I run into this situation, I simply increase the flash power to overpower the ambient, so all the assumptions will work again".

and

"This situation normally only causes a problem outdoors in daylight conditions. Then, the daylight is so bright that you cannot increase the flash enough to overpower it, and you have to use a 'fill' flash concept. It is very rare when shooting indoor flash that you cannot increase the flash power sufficiently to overpower the ambient, so that you can once again control the background and subject independently".

My question:

I am a bit confused about the concept of "overpowering the ambient".

In my understanding (and it may verywell be wrong), you "overpower" the ambient by use of a fast shutter. Isn't this what it is all about - turning background or subject dark by using a fast shutter, and after that you can control the brightness of the subject, by using your flash?

Hope you have the time to clarify this for me.

Thanks!

Frank
(Denmark)

Frank said...

Hi Russ

I now get up one hour earlier every day to be able to read your posts before going to work... Its a fantastic resource!

However it also generates som questions from my side.

Heres a couple:

In an answer to "Bubble" from march 26, you wrote:


"So, in the case that you described, where you changed the shutter from 1/30th to 1/60th, the flash contribution to the image won't change, but the ambient contribution will increase by one stop".

The ambient contribution will increase? I dont get this. Maybe I read it the wrong way, but shouldnt it be the opposite?

Also, in the same answer, you wrote:

"...When the ambient light is bright enough to significantly affect the subject, then changes of shutter speed will change the brightness of the subject as well as the background. The background will still be affected more than the subject".

and

"When I run into this situation, I simply increase the flash power to overpower the ambient, so all the assumptions will work again".

and

"This situation normally only causes a problem outdoors in daylight conditions. Then, the daylight is so bright that you cannot increase the flash enough to overpower it, and you have to use a 'fill' flash concept. It is very rare when shooting indoor flash that you cannot increase the flash power sufficiently to overpower the ambient, so that you can once again control the background and subject independently".

My question:

I am a bit confused about the concept of "overpowering the ambient".

In my understanding (and it may verywell be wrong), you "overpower" the ambient by use of a fast shutter. Isn't this what it is all about - turning background or subject dark by using a fast shutter, and after that you can control the brightness of the subject, by using your flash?

Hope you have the time to clarify this for me.

Thanks!

Frank
(Denmark)

Alex said...

Hi, I am enjoying this very much. I need your help if possible. When I use SB800 on camera(ttl without BL) I get brighter pictures (especially the background) vs the ones I get with the same settings but off camera(D90 in commander mode), using ttl in all situations.

robinbajaj said...
This comment has been removed by the author.
Anonymous said...

Hi Russ,
I recently shot my first event (as a backup photographer) after reading your blogs..
in this first shot I noticed that flash was not able to freeze the subject movement..

http://store.photogenik.ca/photos/885674696_aiAFz-L.jpg
ISO 900, F/4.5, 1/25
(given that flash fires at 1/1000th of second shouldn't it frozen the motion in this case..)

so I learnt from that mistake and later took another dance shot at a faster shutter speed..
where I was able to freeze the motion ..
http://store.photogenik.ca/photos/885620695_iRmzy-M.jpg
ISO 1600, F/5.6, 1/100

Can you explain why is it happening..
1) is it because flash was not primary in the first shot..
2) how do you make the flash primary (by deliberating underexposing the ambient by couple of stops faster shutter-speed etc.?)
please help,
thanks in advance,
Rooban

Russ MacDonald said...

Hi Rooban,

The key thing to understand is that when you take a flash picture it is really two pictures superimposed; one from the flash and one from the ambient light. The one from the flash is always frozen, since the flash is so fast, but the one from the ambient can be blurred if the shutter is slow.

When you see blur in a flash picture of people dancing, you can be assured that the ambient light is what is causing the blur.

The shutter controls the ambient light, so if you set it too slow, the ambient will contribute significantly, which is exactly what happened in your first
example.

The shutter has no effect on the amount of the flash portion.

When you increased the shutter to 1/100th, you darkened the ambient so that even if there were any blur you probably wouldn't see it. Also, at 1/100th, it will stop minor motion even if the ambient is visible.

Yes, you should deliberately underexpose the ambient in dance shots to eliminate the blur. It will also darken the background, so reduce it only as much as necessary to eliminate the blur on the subject.

Have you read my 'Cookbook' blog article, http://nikonclspracticalguide.blogspot.com/2009/12/camera-flash-cookbook-for-any-lighting.html?

Russ

Caroline said...

Hi Russ,
Thank you so much for sharing your knowledge with us!
It's very inspiring all the help you give and the patience you have to answer everybody's questions!

Russ MacDonald said...

Hi Caroline,

Thanks for the nice feedback!

Russ

man-d said...

Hi Russ,

Thank you for sharing you experience with us. Before I start to come around with all the pictures and post-processing, I have to leave you a short message.
All your writings are very very usefull. I was able to use the flash for the first time at an event without having much time for training and I got some very nice pics.
It was necessary to use TTL and some times TTL-BL with FV lock was very interesting. For sure I learned that all here.

I just was confused when the flash was overheating. Looks not to be a problem with the Sb-900. Just have to wait a moment.

I go without Nikon speedlight experience to the event but I took your words with me.

Thank you.

Russ MacDonald said...

Hi man-d,

Thank you for the kind feedback. I'm glad I could help you!

Russ

f54 said...

Great Stuff,
This blog is so helpful. I'm new to this flash business and need all the help I can get, a friend wants me to take some photos of her evening wedding party. So happy to have found this blog. Thanks.

Russ MacDonald said...

Hi f54,

I am glad you find my articles useful.

Thanks!

Russ

DK Brittain said...

I can't thank you enough....I feel like I have to re-invent the wheel every time I pick up my flash!!!!

Russ MacDonald said...

Hi DK,

You are most welcome! Glad you can use the information.

Russ

ENID said...

I've been learning a lot from all your blogs but need a quick basic summary for shooting with sb 800 on D200 in a restaurant setting. There will be about 5 tables with 6 -8 people each in a private small diningroom. First, there will be a cocktail hour where I assume guests will be standing and moving around and then we will be seated for dinner. What do you recommend would be best settings for a very enthusiastic beginner who is a little afraid she might mess up?

Russ MacDonald said...

Hi Enid,

Your camera settings depend on how bright the ambient light is in that particular restaurant.

Most of the time restaurants are low ambient, and in low ambient you will want the flash to be primary.

When you want the flash to be primary, you select TTL on the flash (not TTL-BL).

Select Camera Manual mode, ISO 400, 1/80th, and f/4.

Then put a diffuser on the flash, point the diffuser at the ceiling and shoot.

You should also read my Cookbook blog article here: http://nikonclspracticalguide.blogspot.com/2009/12/camera-flash-cookbook-for-any-lighting.html

Russ

ENID said...

Hi Russ,
You said that increasing aperture increases background exposure. This makes good sense to me. I took 2 pictures f4 and f7.1 at 1/80 ISO 400 manual ttl and the white balance set to flash. The f7.1 was much brighter. Could you explain why this might happen?

Thanks,
Enid

ENID said...
This comment has been removed by the author.
Russ MacDonald said...

Enid,

Something must be in error. Either the camera or the flash must have malfunctioned.

Russ

Claire said...

Hi Russ
Huge thanks for your awesome job at explaining this very complex subject !!! I was always pretty much using similar settings to yours (advised by another user) but without knowing why, and when I (often) got inconsistent results, I couldn't figure out why either !! Now I'm starting to slowly understand the basics, I just read your entries over again during the day, and practice with my D90 and SB-600 at night.
Not a master yet (by far !) but getting more consistent results.
The one thing I have noticed is that my camera seems overly sensitive to center focus point, to the extent that I need to use FV lock consistently for optimal exposure. I always focus on my toddler's eyes (well, one of them anyway, I shoot fast primes often wide open and don't expect both eyes sharp) and have noticed that if I recompose without FV lock, the camera exposes the skin properly but the eyes are slightly underexposed. Does that sound normal to you, and should I just learn to use FV lock as standard ?
Anyway keep up the great work, can't believe Nikon hasn't offered you a position yet ;)
Claire.

Russ MacDonald said...

Hi Claire,

Thanks for the kind words!

Here is what happens when you half-press the shutter:

1) The focus is locked on your toddler's eye. When you recompose, as long as you hold the shutter half-pressed, the focus will remain on the distance of the todler's eye.

2) However, the ambient exposure is not locked. It continues to change the aperture and shutter, depending on what mode the camera is in, until the shutter is pushed the rest of the way. This is one reason I recommend using the camera in Manual mode. Then, the aperture and shutter cannot change when you recompose.

3) The flash power is not locked. The flash power will be metered when the shutter is pushed the rest of the way, based on whatever is centered in the frame. If you use FV Lock while the toddler's eye is centered, the flash will meter the subject properly, and lock in that flash power to be used when the shutter is pushed the rest of the way.

Contrary to many articles written by other authors about the flash, the focus point does not affect the flash power. In regular TTL mode, the only thing that affects flash power is the measured reflection of the monitor preflash. In TTL-BL mode, both the preflash and the distance to the subject is used. It is only the distance received from the lens that affects flash power, and not the position of the focus point.

I wrote another blog on this here:
http://nikonclspracticalguide.blogspot.com/2009/10/does-moving-focus-points-affect-flash.html

The consistancy of the TTL system will normally get you within about a half a stop. You have to live with the +/- 1/2 stop variation.

Anonymous said...

Good evening,i was using nikon d80,sb800 and have some doubt regarding to the flash system.my setting were iso 400,manual mode,ttl with fixed soft box on the flash head,bounced to the wall,105mm macro len,1/200,matrix metering,subject distance 1 meter from camera.the first image was using f3,the whole image look underexpose but when switch to f5,the whole image look brighten and well expose..if i stop down the aperture to f5,my subject should look darker than f3 but why the result was vise-versa.waiting for your answer.thanks.your blog help me a lot.like to view your blog.

Russ MacDonald said...

Hi Anonymous (I wish you would sign your name on your post),

When using TTL or TTL-BL, the system automatically compensates for the aperture you select. For instance, if you select a smaller aperture, the system increases the flash power to make the same exposure.

In your case you changed the aperture and there was a change in the exposure. That indicates you were allowing lots of ambient into the image. The flash contribution to the exposure wasn't changing, but the ambient contribution was. If you want the flash to provide the entire exposure, you have to set the camera controls to eliminate the ambient. That means a high shutter speed. This is why you should always use Camera Manual mode when shooting indoor flash. Then, you can set the aperture and shutter to whatever you want them to be and they stay there.

One more thing that will cause unpredictable behavior is if you were using TTL-BL. You should always use regular TTL for low ambient conditions (indoors under artificial light).

TTL-BL is for bright ambient light (outdoors during daytime), when you are using the flash for fill.

Selecting matrix metering has no effect on the regular TTL flash.

Please read my other blogs for much more information. You might find my "Cookbook" useful here: http://nikonclspracticalguide.blogspot.com/2009/12/camera-flash-cookbook-for-any-lighting.html

Hope that helps,

Russ

Anonymous said...

HI Russ,
previously you said:
If you are using TTL-BL, then the camera metering mode is critical (Matrix is usually best), because the flash uses that metering data to set its power.
I have a question: If I am using camera manual mode, and I am choosing to underexpose the scene to control the exposure of the bright sky, then use my flash to expose for the subjects, does ttl-bl read the meter readings of the camera that show when I half press the shutter button? This meter would show many stops I am underexposed, so it should still be able to know where proper exposure is based from that. (I know that none of the metering choices make any difference to the finished exposure of the photo when using manual mode, they just bias the meter that shows in the viewfinder when I half press the shutter button). I also know that ttl-bl is not available when spot metering is chosen…so say that I am using matrix metering, or center weighted metering.

Thanks for all your generosity!

Russ MacDonald said...

Hi anonymous,

You have hit on one of the most important things to understand about flash photography.

In TTL-BL mode, the flash computer sets the flash power based on the raw data from the light meter in the camera, modified only by the camera ev setting.

The flash computer does not take into account the exposure modifications you have done using the shutter and aperture.

In other words, the flash computer assumes you have centered the meter. This is why I usually recommend you use one of the auto modes (A, S, or P) when using TTL-BL, since the camera will center the meter far quicker than you can.

In TTL-BL mode, the flash power is set by a complex equation involving the raw meter data from the camera light meter, distance to the subject, and the amount of reflected energy from the preflash.

Changing the aperture will change the brightness of the sky and the the power of the flash as it attempts to keep the subject lit at the same brightness as the background would be if the camera meter were centered.

Changing the shutter will only change the brightness of the background, as the flash continues to balance the subject to the background as it would be with the meter centered.

For shooting sunsets, I normally use Regular TTL, so the power of the flash is not influenced by the sky in the background. I use camera Manual mode and set the aperture and shutter to expose the sky correctly, and then adjust the power of the flash using the FEV rocker switch on the flash to set the correct exposure of the subject.

Hope that helps,

Russ

Anonymous said...

Hi Russ, thanks for your reply to my last post.
In TTL-BL mode, the flash power is set by a complex equation involving the raw meter data from the camera light meter, distance to the subject, and the amount of reflected energy from the preflash.
I am still trying to read all of your posts to learn, but in the meantime, is it true that ttl flash and ttl-bl flash both use the preflash system for feedback about the scene I am about to photograph? Please correct me where I am wrong:

Ttl-bl goes 1 step further than ttl in that it uses the camera’s ambient exposure controls on the camera( the settings of iso & aperture & shutter speed), and also the focal distance of the subject( when I focus on my subject the camera figures out the distance from the camera to the subject). Using this information and the preflash, it tries to match the exposure of the background by using the flash to fill in the “shadow” of the subject?

In a way, the camera really doesn’t use the camera’s light meter for it’s calculation of the correct flash output. It uses the RAW DATA, which I take to mean the exact settings of iso, aperture, and shutter speed, regardless if these settings are underexposed or overexposed. In manual camera mode, if I underexpose the scene with my ambient exposure controls (iso, aperture, shutter speed settings) then the flash computer will use these settings, erroneously, to calculate proper flash exposure. The flash computer is not smart enough to understand that these settings are underexposed and will cause underexposure of the flash exposure too.

The flash computer always assumes that the camera’s ambient light controls have been set to “proper” exposure (zero on the exposure meter). For this reason, one of the camera’s automatic exposure modes( aperture priority, shutter priority, or P) will be the fastest way to set the ambient light to “ zero on the exposure meter” ( even though these modes do not actually display a visual exposure meter for us to see).
So you recommend that when I am controlling the exposure of the sky in the background by using my camera in manual mode, that I actually use ttl flash and not ttl-bl flash. In ttl flash mode, the camera will not use the readings of the RAW DATA associated to the camera meter. In this mode, the power of the flash is not influenced by the sky in the background. Ttl flash will use the preflash as it’s feedback to calculate the flash exposure. I should use flash exposure compensation to dial in the desired flash level of the subject.
Does ttl use the distance information of the camera to the subjects that is provided when I focus on them?

Anonymous said...

Is this correct? This would be the perfect scenario to set up for a photo in order to get the camera’s flash computer to give reliable correct exposure:
- the subjects are centered in the photo, because the reflected energy from the monitor preflash is metered by the camera in the center weighted frame. The camera flash meter primarily uses the exposure of what is positioned in the center of the scene to calculate flash exposure.
- When the people are in the center of the scene, it is best if their clothes are “18 percent” gray (joke!)…but it is really true isn’t it? If they are wearing all black, they are underexposed according to 18 percent gray, and the flash will try to increase their brightness level with a longer flash duration. The result will actually be an overexposed photo. If they are wearing all white, the opposite is true.
- The subjects fill the frame of the photo wearing 18% gray. Say I framed the photo so that they did not fill the frame, and lots of the background showed, it would be best if the background were also average tones, aka 18% gray. If the background were dark and the subjects were small in the frame, both the background (which is considered underexposed), and the subjects, would be considered by the camera to be “center weighted”. The flash exposure calculation would try to lighten then scene to an average tone (18% gray) because the background is not that. Really, the camera is fooled. The result would be that the subjects are overexposed by the flash.
- Also, the reflectivity of the scene alters the flash exposure. It would be best if the subjects were wearing 18% grey, and also that this grey was of average reflectance. If it was a shiny relective grey, it would bounce back a lot of light from the preflash into the lens. I guess in this case, it couldn’t actually be considered 18% grey?
I assume that when any of these ideal situations for the camera’s flash light meter are off, the photographer would just dial in flash exposure compensation on the flash? The further away from ideal, the more compensation is required.
Using the situation I was asking about before, what would you advise? When I am shooting a photo of my 2 subjects with the bright overexposed sky behind, I use camera manual mode and expose for the sky, leaving my subjects in shade. I switch the camera to ttl mode, and choose ttl on my flash.
I guess everything depends on how tightly I frame my subjects in the photo? Assuming that my subjects are centered in the photo, should a photo that is more tightly composed produce more reliable flash exposure results than one where the subjects are smaller in the frame?
Can you try to explain the process that the camera would use in this type of photo? Since the camera is not using the raw data from the ambient light controls on the camera, does the camera’s flash meter computer do all the work? As far as I understand it, in ttl flash mode, the camera is really clueless about the level of ambient light in the scene…dumber than dumb. Does the camera really do all of it’s calculation based on the preflash and it’s focal distance? If the camera really doesn’t know anything about the ambient light level, and it fires the preflash, isn’t it just like as if it were firing a flash in the dark?
Somewhere in your posts you mentioned something about how you can fire a photo while being in a completely dark room, and still get the subject to be properly exposed.
So the preflash fires in the dark, the light returns through the lens, the camera’s flash meter computer (which is located within the camera & not in the flash) analyzes the intensity of the light that is reflected back, and then tells the flash to fire for a certain duration for correct flash exposure.
Russ, thanks again for all of your postings. I have been having many “aha” moments in the last 2 days!
Bj

Russ MacDonald said...

To anonymous (please leave your name since I don't know whom I'm talking with)

I would appreciate it if you would read my other blogs. You are asking questions about TTL-BL on the blog about regular TTL.

Here is my TTL-BL blog: http://nikonclspracticalguide.blogspot.com/2008/01/nikon-ttl-bl-flash.html

Most of your questions are answered there.

Thanks,

Russ

Top Rated Cameras said...

wow. this is such a very useful and informative entry especially for newbies like me. I just bought a new Nikon d5000 camera and I'm on the process of learning some basic shots particularly with different light settings and a lot of other stuffs. :) I'm planning to get the SB800 next month and will definitely try out your tips! I learned a lot from your post and I hope you post some more techniques on photography! :D Keep them coming!

Russ MacDonald said...

To Top Rated Cameras:

Thanks for the nice feedback.

I don't make a new post very often, because I am only trying to cover the basics, and those don't change, so please study the posts I have already made and let me know if you have questions. I always answer all questions promptly.

Russ

Kevin said...

Hi Russ!
Firstly very good post. I've been reading a lot into flash techniques and TTL and stuff like that, but I only found out about how the Flash only meters off the centre when I read your post.

I have one question however (and please forgive me if it's already been asked but the posts were so long I haven't read all of em):

TTL is meant to be through the lens. So The flash fires a pre-flash to calculate how much it needs.... through the lens. Therefore shouldn't it calculate how much ambient light there is, and adjust its flash power to match? I thought that's the whole point of TTL. So you can adjust your aperture/iso/shutter speed, and the flash will adjust accordingly to give you the same exposure.

If that is the case... then why would it overexpose when there is too much ambient light? Shouldn't the flash realize that there's too much light, and thus decrease its flash power?

Russ MacDonald said...

Hi Kevin,

You are right that the flash reflection and the ambient are mixed together and they do add.

However, this is the key, the intensity of the preflash is about 10 to 100 times brighter than the brightest ambient. Therefore, the ambient makes effectively zero effect on the flash power calculation.

This is why I say that regular TTL sets the flash power as though you were in a pitch dark room. This is why you should always set your camera to underexpose the ambient in the room by a couple of stops, so it won't add much to the exposure. If you want to allow the ambient to contribute more, then you have to set a negative compensation on your flash to avoid overexposure.

I usually use -0.3 ev on my flash for normal dim ambient rooms where I want brighter backgrounds. This also helps when the subject is wearing dark clothes, which tend to increase flash power.

Outside in bright sunlight the ambient does make a small effect on the power of the flash, but it is negligible.

Gopiramesh said...

Dear Mac,
First of all I would like to thank you for your excellent blog. I am great fan of you. Your explanations are marvelous. Keep it up. You are helping people like me very much. By the by I have a doubt regarding the below line in that you said," when shooting indoors using regular TTL with the camera in Manual mode, you can choose matrix, center weighted, or spot, and it will have absolutely no effect on the images."
I tried some shots keeping my daughter in front of a white wall in TTL mode, Matrix metering in normal room light condition it gave me under exposed images. Then I made FEC about +1, Then I got correctly exposed images.
Again I took a snap without white wall it gave me correct exposure in TTL mode
I think the meter influences the flash. Am I right.can you explain?
by
Ramesh

Gopiramesh said...

Dear Mac,
First of all I would like to thank you for your excellent blog. I am great fan of you. Your explanations are marvelous. Keep it up. You are helping people like me very much. By the by I have a doubt regarding the below line in that you said," when shooting indoors using regular TTL with the camera in Manual mode, you can choose matrix, center weighted, or spot, and it will have absolutely no effect on the images."
I tried some shots keeping my daughter in front of a white wall in TTL mode, Matrix metering in normal room light condition it gave me under exposed images. Then I made FEC about +1, Then I got correctly exposed images.
Again I took a snap without white wall it gave me correct exposure in TTL mode
I think the meter influences the flash. Am I right.can you explain?
by
Ramesh

Russ MacDonald said...
This comment has been removed by the author.
Russ MacDonald said...

Hi Gopiramesh,

The flash is not affected by the camera metering, and in TTL mode, it doesn't matter what metering mode you are using.

However, the flash has its own metering and the white wall is causing a stronger than normal reflection of the monitor preflashes. When the flash sees a strong reflection (ie from the white color) the flash computer thnks the flash power is too high, so it reduces it. That results in an underexposed image.

Whenever I photograph a bride in a white dress, I have to increase the FEC to +1 or more to compensate.

The opposite is also true. A man in a black suit will increase the flash power and his face will often blow out (overexposed).

Russ

Lloyed Valenzuela said...

Excellent!!! Very informative...thanks for posting!

Russ MacDonald said...

Hi Lloyed,

You are most welcome! I'm glad it is informative to you.

Russ

Anonymous said...

hi Russ, thank you for your explanation and writing, i learn a lot about ttl from your blog.
i have 1 question though regarding ttl and auto iso. when i'm using in built flash my auto iso setting will automatic set when i'm using M mode follow my speed and aperture setting to correct the ambient metering and but when i'm using third party flash my iso auto setting seem like not working it only set the highest to iso 400. but when i'm using the in built flash it can be reach to the limit iso i'm setting in my camera. is this normal when using third party flash, or it was same if using nikon speedlights?

Anonymous said...

hi Russ, thank you for your explanation and writing, i learn a lot about ttl from your blog.
i have 1 question though regarding ttl and auto iso. when i'm using in built flash my auto iso setting will automatic set when i'm using M mode follow my speed and aperture setting to correct the ambient metering and but when i'm using third party flash my iso auto setting seem like not working it only set the highest to iso 400. but when i'm using the in built flash it can be reach to the limit iso i'm setting in my camera. is this normal when using third party flash, or it was same if using nikon speedlights?

Russ MacDonald said...

To Anonymous (please sign your name when posting):

I recommend that you turn off auto ISO when using the flash. It does unexpected things just like you indicated.

I have recommend ISO 400 when using regular TTL and ISO 200 when using TTL-BL.

Russ

Tim Feathers said...

Thanks,

I've learned more about flash photography on this blog than every book, manual, and other site combined. I am finally taking some beautiful photos with both my SB600 and SB900 as a direct result of the information you have been so kind to share here. Just wanted to be sure to let you know of the appreciation for your time and effort.

Russ MacDonald said...

Hi Tim,

What great feedback! I'm glad you find my articles useful.

Thanks,

Russ

Umesh said...

I learned from your website more than from any other website. But I am wondering if you stopped writing. Thanks for the great post.

Anonymous said...

This blog has helped me understand how my flash works. Thanks

Anonymous said...

Hi Russ,
by chance I came accross your blog about Nikon's CLS.
Great work! I really appreciate that you share your findings. It saves me quite some time because I can learn from your examples as well as from readers comments and just go and practice in field.

Regards, HaJo

Anonymous said...

Hi Russ,
I want to know if there is an iTTL cord that would be long enough to use so that I could go higher than the FP 320 sync speed when the ambiant light is way too strong.
Would that work without reducing the power of the flash?
Thanks,
Pamela
pjcoll@telus.net

Russ MacDonald said...

Hi Pamela,

The only way to set the shutter speed higher than the flash sync speed is to select Auto FP High Speed Sync.

Unfortunately, FP mode reduces the maximum flash power substantially, meaning you have to be quite close to your subject to get proper flash exposure.

The flash cable has nothng to do with FP mode. When you use a flash cord the camera and flash both think the flash is mounted on-camera in the hot shoe.

Please read the blog article I wrote about Auto FP High Speed Sync.

Hope that helps,

Russ

George said...

Hi Russ,

Can you briefly summarise with your suggested settings (metering, camera mode, F-stop, shutter speed, ISO etc.) on camera for the following 4 situations in flash photogrphy:

1. In door with pop-up flash.
2. In door with off-camera flash.
3. Outdoor with pop-up flash.
4. Outdoor with off-camera flash.

Equipment: Nikon D300 with a SB600 flash.

Thanks,
George

Russ MacDonald said...

Hi George,

Indoors with a pop-up flash follows the same same requirements as indoors with your SB-600 in the hot shoe. Have you read my cookbook blog here: http://nikonclspracticalguide.blogspot.com/2009/12/camera-flash-cookbook-for-any-lighting.html

However, when you move the flash off-camera, the only mode you have is regular TTL. This means that off-camera flash will be automatic as long as the ambient is low (ie, indoors). In this case, all the rules are the same as on-camera.

However, if the ambient is bright (outdoors in daylight), you will be shooting 'fill' flash, and you will have to balance your flash manually to the ambient, since TTL-BL will not be available. I have not covered manual balancing, because it is not simple. It involves lots of trial and error to avoid overexposure. I very rarely use off-camera fill flash, since the direction of the fill is usually not important.

Hope that helps,

Russ

Pug said...

A Godsend!!! Thanks so much for this!!!!

Russ MacDonald said...

Hi Pug,

You are most welcome!

Russ

Anonymous said...

I have sb900, and I want to shoot something during night (outdoor) time, but
unfortunately when Iam using my flash, I can make the right adjustments that will make both the background and the subject to have balance light or simply not a dark background. Do you have any suggestion on this.

Iam using d90 and sb900

Russ MacDonald said...

To Anonymous (wish you would sign your name),

When you are outdoors at night, it is impossible to light the background with the speedlight. This is because the power of the flash decreases by the square of the distance after it passes the subject. This means that nothing behind the subject will receive any significant illumination from the flash unless it is very close behind the subject.

If there is just a little ambient light, you can slow the shutter way down and that will allow the ambient to light the background. You might need shutter settings of 2 seconds or more to get anything in the background to show. Your light meter in the camera will give you the information on what shutter speed to use. It will register light as low as where you need 30 seconds of shutter.

Of course, you will have to use a tripod to eliminate motion blur.

Hope that helps,

Russ

Briano Santos said...

Russ,
I found your blog while doing a google search for "FP Sync explained." It was so helpful! As I started reading more I decided to do another search for "FV Lock explained" and your site came up again! I was so happy to see that you've covered all the bases and I'm sure I don't speak for myself when I say thank you for the time and effort you put into having such detailed explanations. You're making us all better photographers. Just so you know If I'm ever in the Savannah area I'm dropping by your studio and shaking your hand.
BTW I'm a fellow CFII. Based out of the KHWD apt in the SF Bay area. My wife and I are in the "infant" stages of a photography business and have just started to take baby photos. We've begun working on a web site too. You're an inspiration and a great educator!
I am continually impressed and amazed that you take the time to respond in great detail to everyones questions. There's so much more to learn by reading through the comments section.
I know you've mentioned before that you're not interested in writing a book but I must say maybe a small "getting started with your nikon flash" guide would be a best seller :0) Think about it!
Take care Russ and thanks from me my wife and the thousands of others out there learning from you.
-Briano Santos

Russ MacDonald said...

Hi Briano,

I really appreciate the kind comments!

I've thought about putting together a book on the basics of flash, but I would have to do most of the work over and get releases and all sorts of stuff. The way it is now, in my blogs I've just used photos from my weddings and events without getting specific releases. When you publish a book, you have to be very careful to get written releases from everyone in it.

Also, the newer flashes are much more forgiving that the older flashes and I have not fully tested them.

No, a book sounds way too much like work. This blog is just a hobby to me.

If you are ever in Savannah, please give me a call and we can get together. I love to swap both photography and flight instructing stories!

Russ

Jennifer said...

I just found this blog. Thank you!! I'm such a newbie with flash photography. The manuals on my SB-600 had my head spinning.

This article was well written and understandable. I will have to read and re-read it to get the concepts down, but it didn't feel like I was trying to decipher Klingon.

Russ MacDonald said...

Hi Jennifer,

Thanks for the nice feedback! I'm glad my articles help you.

Be sure to read all the questions and answers after each article, because I added more details there on some of the more confusing issues.

Klingon? So that's the language in the SB-600 manual! LOL

Russ

jonycliff said...

Al fin una persona hace simple lo que todos hacen complicado.
Gracias, y espero leer otros blogs suyos en el futuro.
Saludos desde Argentina!

Russ MacDonald said...

Hi jonycliff,

I am glad you find my blogs useful!

Yes, most other descriptions of this system are very difficult to understand. I tried to simplify it as much as possible.

Russ

Daniel said...

Russ, Thank you so much for this blog. I agree with all the other comments as your blog explains more than all the books I have read on the subject. I would like to ask a basic question. When you walk into a dimly lit room, do you set your camera to expose the ambient light and then flash the subject? ex: room is F4 at 1/60th SS ISO 200. Do I use these settings on my camera and then flash? In other words, how do you determine how to set your camera to begin with? Thanks so much for your expertise and valuable time. Dan

Russ MacDonald said...

Hi Daniel,

Thanks for the nice feedback!

After you gain some experience with your flash, you will be able to judge the ambient with your eye and simply know what camera settings you should make without any effort at all. But while you are learning, you have to use the meter in the camera to help you.

The short answer for indoor flash primary shots is to set the camera so that it would underexpose the room by about two stops with the flash OFF, Then, turn the flash ON and take the shot.

I have written all the details about this procedure in my 'Cookbook' article. Here's the link: http://nikonclspracticalguide.blogspot.com/2009/12/camera-flash-cookbook-for-any-lighting.html

Read that article and I think it will answer all your questions.

Russ

Daniel said...

Russ, thank you for your answer. I have tried so hard to find that one little beginning point and now can actually go out there without guessing where to begin. Thank you, thank you, thank you. Dan

Daniel said...

Russ, I posted before I could ask this final question. As far as a beginning point for shooting flash, can I assume the reason for taking an ambient reading and then setting the camera to approx 2 stops lower is because the flash itself will add light to the ambient? Again, thank you so much for your help, your willingness to share your knowlege. Daniel

Russ MacDonald said...

Hi Daniel,

Yes! That is exactly right. In regular TTL mode, the ambient light is not considered by the flash system, so whatever ambient light there is adds to the flash on the subject, and if you don't keep the subject at least two stops underexposed from the ambient, the subject will often end up overexposed.

Russ

pixels4u said...

Hi. I was recommended to look at your site. As a photographer for more years than I like think about, I have started to do a few weddings at a very low level. I've had done 3, but two weeks ago under took a wedding which tested my skills with a D700 to the limit. In desperation I went on to Auto-program for the first time ever and used my SB800 on iTTL or iTTL BL mode. I was so surprised at the consistant results I started a thread on Nikonians. I also stated that my knowledge of Speedlights was low and to me was a dark art. I find your site a real asset in my advancement of Speedlight learning. Great site. My link to the Nikonians thread is: http://www.nikonians.org/forums/dcboard.php?az=show_topic&forum=226&topic_id=33580#33742

Thanks - Richard

Russ MacDonald said...

Hi Richard,

Thanks for the great feedback!

You have stumbled onto one of the best-kept Nikon secrets!

Every Nikon wedding pro I know has a hard and fast rule to go to camera P mode () whenever shooting fill flash outside in bright daylight. We joke that the 'P' stands for Professional mode, because amateurs never use it.

It is also critical to use TTL-BL flash mode for fill to be added properly.

Then, the camera and flash will adjust automatically to do exactly the same thing you would have done manually. First the camera sets automatically sets the shutter to flash sync speed (1/250th on your D700). Then the aperture will be stopped down to control the ambient exposure. Lastly, flash will be added to bring the subject up to the same brightness as the ambient.

It's also important to understand that when adding fill using TTL-BL mode, the power of the flash is determined mostly by the distance to the subject as reported by the D lens. If you turn the head of the flash up (like with a diffuser attached) TTL-BL doesn't work as well, because it has to revert to the normal monitor preflash to set its power, and in bright daylight the monitor flash doesn't always get a strong enough reflection to set the power right.

Have you read my 'Cookbook' blog article? Here's the link: http://nikonclspracticalguide.blogspot.com/2009/12/camera-flash-cookbook-for-any-lighting.html

I will also check out your post on Nikonians.

Russ

shahrooz said...

thank u for your helpful text that i accidentally found , now work sb900 better for me.
shahrooz from iran

Russ MacDonald said...

Hi Shahrooz,

I'm glad you find my articles useful! Be sure to read all the questions and answers following each article. There is lots more information there that has not been transfered to the article.

Russ

shahrooz said...

thank,s for your immediate answer.
if u could these answer and questions to another article bring !
because of my poor english and my hard work (crm in an industrial auto company) from 8 to 20 , i read slowly .
nikon co must thank,s u , these useful tips can nowhere as equipment manuel found .
how can u these blog in better search in google search engine bring ?
shahrooz from iran

Russ MacDonald said...

Hi again Shahrooz,

I think you are asking me to capture the questions and answers into another article.

I may do that in the future, but I don't have time right now. My photography business keeps me very busy.

Russ

Anonymous said...
This comment has been removed by a blog administrator.
mel said...

I really appreciate what you are doing here, these are really great articles and examples.
I must say they are the best ones I have found on flash photography up to now..Flash photography was always a very complex thing to me so I always avoided using it,but now that I follow your blogs and read your articles I really find myself enjoying to shoot with flash..Thank you so much for the wonderful explanations..

There's one thing not clear for me: you said:
Now, decrease the shutter speed to 1/10th sec and shoot again. The background will be brighter, but the subject will be the same brightness as before. Also, the subject will be sharp, but the background may also show some motion blur, because 1/10th sec is too slow to hold the camera perfectly still (unless you use a tripod). Since the flash was primary on the subject; ie, the ambient was overpowered by the flash, and the flash duration is normally faster than 1/1000 sec, the subject will be sharp with no motion blur.

while shooting my baby girl with 1/10 shutter speed,wouldnt there be a motion blur evenif I use a tripod? I haven't tried it yet but in my mind a portrait could never be sharp with a 1/10 shutter speed although I use a tripod and ttl flash bec the apperture will be open for a 1/10 of a second and my baby girl would definately move during that time..
You said it(1/10ss) is just a matter of holding the camera perfectly still but I dont get how can a portrait be sharp with a 1/10ss if I can manage to hold the camera still fe with a tripod..

Thank you again for the wonderful articles, they really helpmed me a lot..
Melih

Russ MacDonald said...

Melih wrote: "There's one thing not clear for me: you said:
Now, decrease the shutter speed to 1/10th sec and shoot again. The background will be brighter, but the subject will be the same brightness as before. Also, the subject will be sharp, but the background may also show some motion blur, because 1/10th sec is too slow to hold the camera perfectly still (unless you use a tripod). Since the flash was primary on the subject; ie, the ambient was overpowered by the flash, and the flash duration is normally faster than 1/1000 sec, the subject will be sharp with no motion blur."

The key point you are missing is that when the flash greatly overpowers the ambient, there is zero exposure caused by the ambient. The only time blur would occur is if the ambient was bright enought to cause a portion of the exposure. If the flash is the only contributor to the exposure on the subject, and it occurs in 1/1000th sec, then the subject will be sharp.

Now, I realize that at 1/10th sec exposure, the ambient would have to be very very dark for no ghosting to occur. If the ambient produces even a small amount of the exposure, then any motion of the subject will appear as a ghost around the sharp 'flash frozen' image.

If you shoot pictures of your baby girl at 1/10th sec shutter, and the ambient is normal room brightness, then you will probably have some ghosting if she moves at all. However, turn off all the room lights and shoot again. She will be sharp at 1/10th sec with no ghosting.

Hope that makes sense,

Russ

mel said...

Hi Russ,
first of all let me say that I have really learned a lot from you, thx again for making such a complex topic easy to understand and practise.

I have been following your suggestions with success and joy.

I have a small problem I have just realized and wanted to ask you the possible reasons for that:

some of my (not all) flash photos lack sharpness..

below is the exif data of a photo
which I find soft although with my settings it had to be sharp..

nikon d7000
sb600
f9
1/250s
iso 100
programmed auto
matrix metering

sb600
front curtain
i-ttl-bl -0.3ev

af-s
wide area

on a tripod
vr off
nikkor 35mm


april
17:19 pm
bright and sunny day

the only thing I could think of for a possible reason for this lack of sharpness is:

I set the camera to the self timer mode and adjusted to take 8 photos with a 2 second shutter release delay.
Nearly 5 or 6 photos among 8 lack sharpness..
can it be bec of this settings or sth else?

thx in advance
Melih

Anonymous said...

Great explanations are lasting, thank you!

Farzad said...

Russ, Thanks for sharing your knowledge. I am reading your posts and am learning a lot from you.

Farzad

Eric Schurr said...

I just want to say i've started reading these posts and they are really incredible. Nikon flash photography is amazing, but it's a mystery. I have four flashes and I know how to synchronize and control them, but i'm always wondering what's really happening "under the covers."

I wish you'd write a book or make a DVD! This material is truly the best i've ever read about Nikon Flash (and i've read many of Joe McNally's books, which is also darn good)

Russ MacDonald said...

Thanks everyone for the nice feedback. Sorry I didn't respond sooner, but I stopped receiving emails letting me know there were comments posted for some reason.

Russ

Anonymous said...

Hi Russ,

Just stumbled over your blog and you made me dust off SB800 that was sitting in the camera bag for some time now. Simply, I gave up on it until now.

I am just at this first posting and already have quick question. I feel that most of material discussed here is applicable to indoor situation where distance to subject is about a third then distance to neighboring wall (basically, given about same lighting of the subject and background, to allow for flash light to fall off for about 3ev, so technique in this blog can be applied easy, if my math is right). My problem is when shooting in small rooms, like 10 by 10 or so. Distance to subject/to wall varies. Sometimes subject is against the wall, sometimes you are "right in the face" of the subject, with lost of room behind subject. Lots of fiddling with the camera and flash is required to compensate from shoot to shoot, hence I gave up on it, just crank up ISO and live with consequences.

Alternative of eliminating ambient light and using flash as only light source don't give me results I personally like. Cast shadows, even with all the bounce of neighboring walls, are not making me happy. I'd rather live with some noise than with what flash does with the scene and cast shadows produced by it. Usually in such situation your frame "see" the light sources, and shadows cast by flash are working against those.

Couple of comments in this discussion got me thinking if it is possible to use smarts of two on board metering systems to further automate the task. First thought was, use P mode and compensate for -3 ev. But you commented that this brings down flash output as well (well, my experience too hence the reason my SB800 is collecting dust).
But, if now you bring up flash output +3 ev, will that do the magic, keep ambient light under control while flash takes good care of the subject? I guess I can make experiment here my self :-)) Thinking is, with subject up against the wall, flash is main light for background too and everything will be lit equally (or will everything be over exposed now?), if there is more distance between subject and wall than between camera and subject, background is at -3 and total subject is 0 (-3+3, and because of the distance to the background flash doesn't contribute to it).

Any other ideas/suggestions for small room settings? Would this setup work?

Thank you, and I'll keep reading!
Sasa

Jennifer Inigo said...

Thank you!!!

AlperMTunc said...

Hello Mr. Russ;
please let me tell you how deeply grateful i am for your blog;
untill i encounter your blog, i was searching for information
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thank you very very much for your unique work.
best regards...

Mark Bowden said...

Hi Russ,
I'm so,so glad I stumbled over your Nikon CLS practical guide and finally I have a better understanding of my pop up and SB600 speedlight.
I thank you for this.
Throughout you quote, with newer cameras the different flash systems, -i-TTL and i-TTL BL will have improved and i-TTL BL will give more consistent results when used indoors.
I am using a D610 with an older SB600 and find it hard to see the difference in i-TTl or i-TTL BL and am now unsure whether to follow your original blog instructions or trust in the i-TTL BL.
Have you a newer updated CLS guide using current Nikon cameras or can you point me in the right direction?
Thanks in advance.
Mark B

MiniD3 said...

Hi Russ
Thank you so much for this blog
I've been annoying you over at Nikonians recently.
glxman, (Gary) in the speed light forum

Had a browse yesterday,
Now starting at item !
Thank you for contributing this excellent information to the Nikon community
Regards,
Gary

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