tag:blogger.com,1999:blog-9113726419970930271.post7773016144589455674..comments2023-05-27T02:33:34.320-07:00Comments on Nikon CLS Practical Guide: 6. Sequence of Events for TTL FlashRuss MacDonaldhttp://www.blogger.com/profile/15288785902650834143noreply@blogger.comBlogger46125tag:blogger.com,1999:blog-9113726419970930271.post-54712545521485875082014-03-06T15:08:52.560-08:002014-03-06T15:08:52.560-08:00Hi, Russ. I found your blog and am reading many ti...Hi, Russ. I found your blog and am reading many times and learning a lot. This time, I want to be really good at flash photography.<br />I have a dumb question.<br />I read "6. Sequence of Events for TTL Flash" and others, and I do not understand why the term TTL(Thru the lens) is included in the TTL flash. I noticed in #6 blog, the flash output level is not determined at all by the 'thru the lens' process. Am I missing something here? Thank you very much. Jason.jminhttps://www.blogger.com/profile/04807397120756777408noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-56413734540686125562014-03-06T15:07:49.172-08:002014-03-06T15:07:49.172-08:00Hi, Russ. I found your blog and am reading many ti...Hi, Russ. I found your blog and am reading many times and learning a lot. This time, I want to be really good at flash photography.<br />I have a dumb question.<br />I read "6. Sequence of Events for TTL Flash" and others, and I do not understand why the term TTL(Thru the lens) is included in the TTL flash. I noticed in #6 blog, the flash output level is not determined at all by the 'thru the lens' process. Am I missing something here? Thank you very much. Jason.jminhttps://www.blogger.com/profile/04807397120756777408noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-31737914324780366062013-04-02T16:42:51.725-07:002013-04-02T16:42:51.725-07:00Hi Scott,
Yes, I believe it is best to leave grou...Hi Scott,<br /><br />Yes, I believe it is best to leave groups that are not in use turned off. There are actually two reasons. Proper exposure is one, and you get extra delay between shutter release and flash for each group that is in use.<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-52982949967706754842013-01-20T00:29:08.005-08:002013-01-20T00:29:08.005-08:00You said:
"I believe that this is why each gr...You said:<br />"I believe that this is why each group alone is purposefully set to underexpose the subject. Then, when multiple flashes are used, like in a studio, the subject is usually exposed properly."<br /><br />Which means to me that I should not leave a Group on in my master if I am not using any flashes in the Group (I sometimes turn them off at the source rather than the remote). I suspect that the software will not detect the absence of preflashes.Scott Campbellhttps://www.blogger.com/profile/10723746354505618229noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-79456347171400088312011-04-13T12:37:41.147-07:002011-04-13T12:37:41.147-07:00Hi Timothy,
The lack of the lens distance info wo...Hi Timothy,<br /><br />The lack of the lens distance info won't affect regular TTL, because the flash power in regular TTL is set entirely by the reflected energy in the monitor preflash.<br /><br />However, the lack of distance infor when shooting TTL-BL will have serious consequences, since about 90% of the power setting information in TTL-BL comes from distance. The monitor preflash is used only as a minor input. I think it will make TTL-BL less reliable.<br /><br />It may be best to stay in regular TTL at all times when using a non-D lens.<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-36168107427536807532011-04-13T07:47:33.236-07:002011-04-13T07:47:33.236-07:00hi, Russ if i'm using old nikon lens with no d...hi, Russ if i'm using old nikon lens with no d for distance does it affect the ttl in system?aaronhttps://www.blogger.com/profile/10766358979791204110noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-3737553596072920272011-02-11T06:07:35.395-08:002011-02-11T06:07:35.395-08:00Hi Alex,
You are exactly right! The Fire Command ...Hi Alex,<br /><br />You are exactly right! The Fire Command DOES ADD TO THE EXPOSURE if you don't filter the flash pulse.<br /><br />This is why Nikon makes an IR filter to cover the commander in the camera (SG3IR Panel). It sits in the hot shoe and the panel part flips down in front of the pop-up flash to block the white portion of the light and allow the IR portion to pass. Only the IR portion is used by the Remote speedlights to control them.<br /><br />It is the white light portion of the flash pulse that will add to the exposure. The IR part doesn't affect the exposure.<br /><br />If you are using an external speedlight as a Commander, then you have to buy a gel IR filter that passes IR and blocks white light, that you attach to the front of the speedlight.<br /><br />However, all that said, the Fire Command pulse is much lower power than the main flash pulse, so you can usually ignore it. I never worry about it in my wedding and portrait business.<br /><br />The only time it becomes a problem is when shooting macros where the Commander is really close to the subject. This is why Nikon made the SU-800 Commander. It has a built-in IR filter and puts out no white light.<br /><br />Very astute question!<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-3545140060327005312011-02-11T02:29:29.142-08:002011-02-11T02:29:29.142-08:00Hi Russ,
Thanks for creating a great website on f...Hi Russ,<br /><br />Thanks for creating a great website on flash.<br /><br />You mentioned that:<br />4. The shutter opens.<br />5. The Commander fires another control sequence telling all groups to fire at the power decided in step 3.<br /><br />Wouldn't the control flash sequence be capture by the sensor and taken into the image exposure since the shutter already opened?Alex Yeaphttps://www.blogger.com/profile/02806558638765915699noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-19505380737663768112010-12-31T06:24:42.765-08:002010-12-31T06:24:42.765-08:00Hi again Richard,
Yes, I would be very interested...Hi again Richard,<br /><br />Yes, I would be very interested to see the sims at SAV. I didn't remember (or maybe I never knew) that you were a pilot. I'm a CFII with Coastal Empire Flight Training out of SAV and LHW.<br /><br />Please email me directly on this at rkmacdonald@gmail.com (since it's slightly off-topic for my blog - lol) .<br /><br />Thanks,<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-460307111161941702010-12-30T21:39:58.091-08:002010-12-30T21:39:58.091-08:00Also, I just noticed that you're located in th...Also, I just noticed that you're located in the Savannah area. By way of a "thank you", and if you're interested of course, I'll get you in to see the sims when I'm next there for recurrent.RWChttps://www.blogger.com/profile/11872973807868940278noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-86225002413369320032010-12-30T20:40:08.686-08:002010-12-30T20:40:08.686-08:00Thanks, Russ, your explanation makes sense to me n...Thanks, Russ, your explanation makes sense to me now (not sure why it wasn't last night). That would explain why the SB-900 was happier. <br /><br />Of course the real issue is that the SB-600 only THOUGHT it was out of power. It definitely was not. When it fired at full power and gave the 3 beeps, it totally blew out faces. The whole process was made more difficult because I had to lock the tripod down and couldn't center up on the faces, hit FV lock, and then fire because I had to be in the fool picture myself. All the more reason to continue explaining to my wife why I have to be behind the camera and not in front of it! :-) (I hate having my picture taken). <br /><br />Again, thanks for your insight, both on my specific problem and in general in your blog posts. They have helped me tremendously and have helped me work out what was going on in this case and what I would have needed to do to fix this case.<br /><br />Have a safe and happy 2011.RWChttps://www.blogger.com/profile/11872973807868940278noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-12305029054779190262010-12-30T19:48:26.368-08:002010-12-30T19:48:26.368-08:00Hi Richard,
I looked at your picture and it is ve...Hi Richard,<br /><br />I looked at your picture and it is very nice, but of course, I can't really tell much from a small jpeg like that.<br /><br />However, I do know that at f/8, -1.7 ev, ISO 200, and in a reflecting umbrella, the SB-600 is often not powerful enough to supply the required amount of power that the flash computer calculates. I think that that's why it was beeping 3 times - not because it wasn't receiving the 'stop' signal. In fact, there is NO 'stop' signal in the Nikon CLS.<br /><br />Dark clothing makes the problem worse, because the flash computer tells all the speedlights to fire at a higher power level than normal. The SB-600 at -1.7 ev was probably on the brink of maxed out with light colored clothing, and when you put the dark clothing in the picture, it did not have enough power to supply what was being requested. However, the clothing in the image is really not that dark, so it probably did not increase substantially over the lighter colored clothing.<br /><br />The speedlight will not give the 3 beeps if it doesn't receive the command that tells it to fire at a power higher than what it can deliver.<br /><br />In the Nikon CLS there is no 'quenching' signal; ie, no 'stop' command.<br /><br />The flash computer calculates the power that each flash needs to fire at, and sends the setting out to the flash during part of the preflash sequence. Each speedlight sets itself to the power that was sent to its group and waits for the 'Fire' signal.<br /><br />The 'Fire' signal is the last signal sent out by the Commander, right after the shutter opens fully, and that fires all the speedlights at the power they have stored.<br /><br />If a speedlight has been asked to fire at a power higher than it has available, then it fires at full power followed by the 3 beeps.<br /><br />That said, a speedlight can also make errors receiving the preflash commands if the room is too big. Your SB-600 may have been making errors, but, no matter what else was happening, at f/8 and ISO 200 in an umbrella, down -1.7 ev, I'm pretty sure the SB-600 was out of power.<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-41226027245128135802010-12-29T21:06:08.190-08:002010-12-29T21:06:08.190-08:00Hi Russ,
Thanks for your reply. I fear I may not ...Hi Russ,<br /><br />Thanks for your reply. I fear I may not have explained my question clearly enough. The issue wasn't that my images were blown out, per se, but that the SB-600 wasn't hearing the stop command. I know this because it was giving me the 3 error beeps and was clearly firing at 1/1 when that happened. When it got the stop command, it was clearly firing at less than 1/1, even with the dark clothing. Neither speedlight was being asked to do anything near full power. <br /><br />The room was very dark and the point of the 1/6 shutter was to get the Christmas tree lights to appear in the background. Unfortunately the room is pretty much as you described as worst case: 2-story ceiling and 16x20. <br /><br />I was using the 600 as the accent light through the shoot-through umbrella and was running with it at -1.7ev. <br /><br />I did eventually get the shot I wanted, but not without some seasonally-inappropriate swearing at the equipment, as you can see at http://www.facebook.com/photo.php?pid=1445736&l=384ebc4f56&id=1635221335<br /><br />RichardRWChttps://www.blogger.com/profile/11872973807868940278noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-87400843460670226852010-12-29T08:16:53.399-08:002010-12-29T08:16:53.399-08:00Hi Richard,
I assume you are aware that dark clot...Hi Richard,<br /><br />I assume you are aware that dark clothing will cause an increase in flash power. I have seen increases up to 1 to 1.5 stops compared to light colored clothing.<br /><br />However, even 1.5 stops wouldn't be enough to totally blow out the image. It will blow out faces, though.<br /><br />Maybe the SB-600 stopped working correctly?<br /><br />Or maybe you accidentally changed its group to Manual mode?<br /><br />One more thing that jumped out at me. You were at ISO 200 and f/8. In my experience, the SB-600 doesn't have enough power to blow out the image at those settings when in an umbrella.<br /><br />You also mentioned that your shutter was at 1/6th sec. That's extremely slow for flash photography. Unless your room was extremely dark, the ambient would have been contributing strongly to the image. Is it possible that it was the ambient added to the flash that was blowing out the image?<br /><br />The SB-600 may not go to as low a power setting at minimum as the SB-900 (I'm only guessing as this is not spec'd).<br /><br />Why would you set your shutter so slow? <br /><br />The fact that it did not work with the SG-3IR was probably not significant. It does reduce the power of the command signals. However, I have never had that problem indoors with white walls and ceiling unless the room was very large (ie, bigger than 20x20 and with 18 foot ceilings).<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-71290793472430788222010-12-28T16:09:13.926-08:002010-12-28T16:09:13.926-08:00I was shooting a family portrait last night and ha...I was shooting a family portrait last night and had some very strange behaviors running wireless and am hoping you might have some ideas what was causing it. I had an SB900 in group A shooting through a trigrip and an SB600 in group B shooting through an umbrella, using the pop-up on my D300 as the commander with no contribution from the pop-up. I had the SG-3IR on the camera as well to block its reflection from a picture in the background. Ambient light was very low and the room is entirely white so the command signals should have been bouncing all over the place.<br /><br />I worked to get our marks set up and the compensations correct (what a pain when you have to be in the picture yourself) before having everyone change into our photo clothes. Everything was working well and reliably.<br /><br />Photo clothes were darker so I expected that I might have to tweak compensation but expected iTTL to make most of the adjustment automatically (camera was ISO 200 f/8 1/6 M mode, not that it matters). Suddenly the SB600 stops hearing the "stop" command and fires 1/1, blowing everything out of the water. I tried removing the SG-3IR, I tried putting an SB900 on the hotshoe as a commander, aimed right at the SB600's IR window, nothing worked. I put the SB900 commander on an SC-29 cable to move it closer to the SB600 and that didn't help either. I swapped out the 600 and put the 900 from the camera in the umbrella as group B remote. I still couldn't get it to stop with the SG-3IR in place but at least it worked reliably without it. Obviously, if I owned an SU-800, I would have tried that but that wasn't an option. In the end, I got the it to work with the 2 900's and the pop-up unshielded and just photoshopped out the reflection from the pop-up.<br /><br />That said, I'm stumped as to what might have caused the "malfunction". Got any ideas? This was really my first chance to work with more than one light and I've never seen this problem working with just the SB600 off the camera.RWChttps://www.blogger.com/profile/11872973807868940278noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-39514384774148839002010-06-08T12:23:01.007-07:002010-06-08T12:23:01.007-07:00Hi Anonymous (I wish you'd sign your name),
T...Hi Anonymous (I wish you'd sign your name),<br /><br />Thanks for the nice feedback!<br /><br />You are absolutely right. The last command (the Fire Command Sequence) is sent to the remotes after the shutter opens, and yes, it can affect the exposure.<br /><br />However, the command pulses are very low power, so usually, the effect of the fire sequence on the exposure is negligible.<br /><br />But, if you are very close to your subject, then you can sometimes see its effect. Often in a portrait you can see an extra small catchlight in the subject's eyes from the fire sequence.<br /><br />Regards,<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-1513703080718539932010-06-08T09:47:56.475-07:002010-06-08T09:47:56.475-07:00Thank you for your superb blog! One of the finest ...Thank you for your superb blog! One of the finest corners on the Internet.<br /><br />You said that the order in wireless mode is this:<br /><br />4. Shutter opens<br />5. Commander fires another control sequence<br /><br />Doesn't this mean then that the control sequence affects the final image? I would have thought that the commander fires its last control sequence, then the shutter would open, and then all flashes would fire.<br /><br />Can you please comment on this? Thank you!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-19553060449354379322010-01-06T09:36:44.597-08:002010-01-06T09:36:44.597-08:00Hi Henrick,
It appears that some cameras underexp...Hi Henrick,<br /><br />It appears that some cameras underexpose while others do not. I think it may be a calibration issue, but I have never sent one back to Nikon to have it adjusted.<br /><br />I see no reason why it should underexpose when using only a single on-camera flash, but that's exactly what my D200 does. On the other hand, my D3 hits the exposures almost perfectly.<br /><br />Thanks for the compliments!<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-15542942398288962202010-01-06T06:43:45.242-08:002010-01-06T06:43:45.242-08:00Hi Russ,
first thank you for this blog, I've l...Hi Russ,<br />first thank you for this blog, I've learned a lot here, and I don't think there's any other site with so good explanations how to use Nikon flashes.<br /><br />I've recently switched from D90 to D300, and experienced the same you describe here: when my SB-800 or SB-600 is used wireless, I get strong underexposure. I'd say "at least +2/3" FV compensation required to have similar results to the same flash used on the hotshoe, but you're probably right, and it could be even more than a full stop. <br /><br />It's relieving to learn this is normal and not a strange misbehaviour of my D300, but still find it strange as I don't recall anything like this from the time I used my D90... <br />I don't have it any more, so cannot check it, but I do believe even if it was also underexposing, it couldn't be as strong as on the D300.<br /><br />Maybe I'm wrong of course and D90 was like this, but do you think all Nikon bodies behave the same in this respect?<br /><br />It does not really make sense to underexpose when there's only one remote flash used.<br />(or is it perhaps that the camera does not know how many flashes might be in a single group?)<br /><br />Thanks,<br />Henrikrealthkhttps://www.blogger.com/profile/13495594846540554434noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-30996076298633214462009-10-03T16:05:17.848-07:002009-10-03T16:05:17.848-07:00Hi Jonas,
You may very well be correct.
The reas...Hi Jonas,<br /><br />You may very well be correct.<br /><br />The reason I don't know is that I never allow the master flash to contribute to the exposure, so I have not tested it.<br /><br />I realize that when you have a camera without a built-in commander, you have to use an external master in the hot shoe, and you may not own three flashes, so you probably have to allow the master to contribute.<br /><br />I normally use an SU-800 as a controller on my D3 and I use at least two SB-800s in umbrellas.<br /><br />Maybe your post will benefit someone else who does use the master to contribute to the exposure.<br /><br />Thank you,<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-5967707798827251832009-10-03T13:20:32.036-07:002009-10-03T13:20:32.036-07:00Hi,
I am using a D60 (whithout commander) and an a...Hi,<br />I am using a D60 (whithout commander) and an attached SB-900 as a master flash, and a SB-600 as remote.<br /><br />I discovered that the compensation is about 1.7 ev as you say, but the master flash seems to be uncompensated. Hence, the groups A, B, and C are compensated but M are not.<br /><br />Am I right?Jonasnoreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-33353571659122885992009-08-26T06:33:39.564-07:002009-08-26T06:33:39.564-07:00Hi Daniel,
What you are seeing is normal, except ...Hi Daniel,<br /><br />What you are seeing is normal, except it should be more like 1 to 2 stops instead of 2-3 stops. I actually wrote about this in my blog #6:<br />http://nikonclspracticalguide.blogspot.com/2008/02/so-what-really-happens-when-you-use.html<br /><br />In summary, the Nikon system sets the power of each external group about a stop and a half low on purpose, to prevent overexposure where two or more groups may be overlapping their light (like in the studio shooting portraits).<br /><br />So, if you are using only a single wireless flash, you should set your flash compensation to about<br />+1.3 ev as a starting point.<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-53063888304337942772009-08-26T02:00:26.022-07:002009-08-26T02:00:26.022-07:00Hi Russ,
Great Website, I still don't know wh...Hi Russ,<br /><br />Great Website, I still don't know why Nikon don't do more for their customers and provide some tutorials/FAQs for CLS as it can be quite complicated.<br /><br />My question related to getting the best from the CLS/camera metering interaction. I am using a D200/SB600 combo and find that when I am using the SB600 wirelessly off camera with D200 pop up in commander mode, I seem to get 2-3 stops underexposure (more so when trying to light a subject whilst deliberately trying to underexpose the background). When the flash is on-camera I don't seem to get this issue or at least not as bad.<br /><br />Thoughts?Danielnoreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-20738111909496346992009-08-10T05:19:50.784-07:002009-08-10T05:19:50.784-07:00Russ,
Thank you for your answer (and for all your...Russ,<br /><br />Thank you for your answer (and for all your blog, of course!)<br /><br />Best regards,<br />Gilles.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9113726419970930271.post-221096488511362752009-08-09T15:00:53.452-07:002009-08-09T15:00:53.452-07:00Hi Gilles,
I don't own an SU-800, and one of ...Hi Gilles,<br /><br />I don't own an SU-800, and one of my personal rules is never to write about products I don't own.<br /><br />I have read that the SU-800 has more range under some circumtances and less under others, but I can't verify that.<br /><br />I do know that if you use an SB-800 as a commander, and you put a Gary Fong Light Sphere on it that you get 360 degree coverage so that remotes can be placed slightly behind the camera position. I don't think this would be possible with an SU-800.<br /><br />I also know that you can tape an IR diffuser (Nikon SG-3IR) to the SB-800, and it will mostly eliminate the visible preflash, and the commands are still is diffused by the LS II just like when using visible light and units behind the camera work just fine.<br /><br />RussRuss MacDonaldhttps://www.blogger.com/profile/15288785902650834143noreply@blogger.com