Has flash compensation been applied to the camera or speedlight?
Is the subject very dark or very bright?
This can cause the flash metering to misread the required exposure. If there is a lot of black, the flash user more power to lighten the dark images. If there is a lot of white, then the flash under exposes so not to overexpose the whites.
Ambient lighting could have also caused a problem.
Are you shooting in a bright scene using the flash for fill?
I'm having an issue in that situation, with both a Metz flash and the SB-400. Since it can happen with either flash, and happened with both the D700 and now with the D800 it must be something that I am doing.
D800 I still own an F100; do you think film will make a comeback?
>What is the camera metering set to? In matrix metering the >flash will go to iTTL-BL.
Actually, with the SB900 flash, you can select regular TTL when using any metering mode on the camera, including matrix metering. That's because the camera metering mode has no effect on regular TTL. However, you must use either matrix or center weighterd metering when using TTL-BL flash. If you select spot metering while the flash is in TTL-BL mode, it will force the flash to regular TTL mode.
This all makes sense, because for TTL-BL mode to work correctly, it must be able to determine what the ambient light strength is. If you spot meter on the subject's face, you have no idea what the ambient strength is, so TTL-BL could not possibly work.
>PS Whats your opinion on Manual flash (ex. 1/8th power vs. >your method you > >described above?
Manual flash works great when the distance to the subject is fixed. However, in any situation where the subject is moving, Manual flash is not a good choice.
In your particular situation, if you were sure that every handshake would be at exactly the same distance and you were not moving, then Manual flash would work just fine.
The power setting of 1/8th power is good for only one particular distance depending on how you set the ISO, aperture, and shutter. If you vary any of these three variables, the correct distance for 1/8th power changes.
>The power setting of 1/8th power is good for only one >particular distance depending on how you set the ISO, >aperture, and shutter.
Russ, I’m surprised to see you include shutter speed for I was under the impression that for the most part shutter speed has no affect on flash output.
But Bob for me still leaves out pertinent information and a bit of confusing information. For example in his OP he infers he was using iTTL, but in his reply to DaddySS in response #2 he states “matrix metering iTTL-BL-HP”. I must admit I don’t own a SB900, but I find no reference to HP in the SB900 manual; perhaps he meant FP. But I did notice unlike my SB800, the SB900 has a choice of 3 illumination spread patterns. It would seem that if Bob had center-weighted selected it could very well have caused a hot exposure especially if it was at a distance that was closer than minimum power would allow at ISO 800.
I can’t help but think at this point a sample image would be immensely helpful.
Wed 06-Jun-12 09:18 AM | edited Wed 06-Jun-12 09:24 AM by elec164
Thanks for the sample image Bob, and perhaps it will help Russ make a more informed opinion. To say the least it’s not what I envisioned, and unfortunately for me it raises more questions than answers.
For example in one of your replies you said you were shooting at 200mm with the flash manually zoomed to 135mm. Yet the EXIF data states that image was taken at 85mm. You also stated the flash was set for a -1/3 compensation, but the EXIF data also says you had an EC of -2/3. If I understand Russ’s information correctly the EC would also affect the flash exposure and the two settings would be additive. But that would be beneficial not harmful to your situation IF the subject distance was great enough for minimum flash output. As to the distance, the EXIF data suggests about 15 feet. At ISO 800 and f/5.6 at 1/128th power the subject distance would be around 8 feet, so the flash should have been able to reduce power enough to provide a correct exposure.
So perhaps it was not one particular thing or setting, but a combination of circumstance that caused the skin tones to blow out like that.
So I will be anxiously waiting to see how Russ analyzes and replies to your sample image.
Edited to add: A thought just came to me, and I’m curious. Was there a strong spot light on the subjects that would have made them brighter than the surrounding ambient lighting?
Wed 06-Jun-12 09:52 AM | edited Wed 06-Jun-12 10:12 AM by elec164
OK, after looking at this more this morning and letting the caffeine kick in, more thoughts come to mind.
Now again I’m not very experienced with flash and am using this as a learning experience as well as trying to help. But there is something troubling me about this image. Perhaps those more knowledgeable about this can help me straighten out my confusion and in the process help you.
For example you said these were handshake shots up on stage. Judging from the perspective, you were not on the stage and shooting upward slightly correct? If that’s the case and the flash was the primary illuminant, some of the shadow details puzzle me. For example I would think given the angle of flash, there would not be such a strong shadow under the mortar board of the student, under the diploma and the students back.
Those shadows would seem to indicate a theatrical type stage spot light higher up than your flash would have been. It also would tie in with MarkF’s comment about a bright scene using fill flash. After all you did say you were using iTTL-BL. In that case if there was a bright spot light, then it could be possible that the skin tones were illuminated sufficiently that your shutter speed, aperture and ISO settings provide a correct exposure. If you add flash on top of that, even at fill flash levels you could potentially over-expose those areas.
Wed 06-Jun-12 10:49 AM | edited Wed 06-Jun-12 10:49 AM by elec164
>Hi, > >I have learned, hard way, my SB - 800 (Ref. Photo) should >have been in centered metering mode and not w/fill light enabled
Keep in mind; I believe the SB800 is a bit more powerful than the SB900 illuminant wise.
All well and good, but it still doesn’t jive with me and the shadow detail. So you are saying that with the sample shot you were using an SB800 not the SB900? You are now saying you were getting good exposures with the SB900 but the SB800 was giving you trouble???
All that considered, the shadow detail still puzzles me and suggest the flash provided minimal illumination, but sufficient enough to cause the skin tones to go over the top.
As an example of what I’m trying to say and point out, this is one of the shots I took at my clubs Obedience Trials using an SB800 and D7000 in iTTL with a Gary Fong UC, center weighted metering, f/3.2, 1/40th and ISO 100 at 34mm (about 50mm FF equivalent) and about 12 feet (using my meager skills!! ).
The ambient lighting played a minor role in the exposure with the flash being the primary illuminate I would think. I was on one knee trying to get a better perspective on the dog (after all the dog is the star ) with the flash on a bracket placing it at about shoulder level of the people. You’ll note that the shadow under their chins is minimal, and the shadow of the dog on the jump is less than the shadow cast by the diploma in your shot.
That suggest to me that there was stage lighting that properly illuminated the faces, and the flash pushed it over the edge. If I wrong with that trend of thinking then I would appreciate those more knowledgeable to correct me to help both of us learn. Granted your situation appeared to be a difficult scene to deal with DNR wise (which suggest that ISO 800 probably hurt more than it helped).
Interesting, this shot indicates you removed the EC. It also seems the skin tone of the person handing out the diploma is similar to the ones in the other shot, and similarly seems it is a bit hot. On the other hand the student receiving the diploma this time has a skin tone hthat's a bit darker and not as reflective, and seems well exposed but perhaps still a bit hot.
An interesting set of circumstances and quite a learning experience.
I was pleased with the overall exposure, but upset with myself with the shadows. I thought I set them far enough in front of the jump to avoid them, note to self for next time. I also wondered if I should have underexposed the ambient a tad bit more, but then that would have exasperated the shadow issue I would think.
Another thing I struggle with is making sure the background clutter is not distracting. Fortunately I noticed that in my original setup the duct work was coming out of the judges head and I had them move a bit to avoid it.
I am beginning to think you were using regular TTL. That would be consistant with both images.
In the first, the center of the frame was very dark, and the flash increased power trying to expose the dark areas to standard brightness. This overexposed the faces.
In the second image, there is a lot of light colored material in the center of the frame, which made the flash set a lower power.
In my experience, dark clothing like this can cause the flash to fire as much as +2ev too high. This type of shot is tricky, and you have to zoom in on the faces and fire the FV Lock first. Once that is done one time, all the rest of the shots will be right, as long as you don't change distance. It's just like using Manual flash after you lock in the correct power. Also, the FV Lock gets a more accurate exposure lock when you use a white face to set it. A dark face will set it too high.
Oh, one more thing, you have to be very careful when zooming in on the face with a lens that has a variable aperture. You have to make sure you are using an aperture that doesn't change. When you zoom in on the face, the aperture must be the same as the one you will use for the shot, or the FV Lock won't lock the correct power level. This is another big advantage of constant aperture lenses. They are so much easier to use for this type of shot.
>OK, after looking at this more this morning and letting the >caffeine kick in, more thoughts come to mind. > >Now again I’m not very experienced with flash and am using >this as a learning experience as well as trying to help. But >there is something troubling me about this image. Perhaps >those more knowledgeable about this can help me straighten out >my confusion and in the process help you. > >For example you said these were handshake shots up on stage. >Judging from the perspective, you were not on the stage and >shooting upward slightly correct? If that’s the case and the >flash was the primary illuminant, some of the shadow details >puzzle me. For example I would think given the angle of flash, >there would not be such a strong shadow under the mortar board >of the student, under the diploma and the students back. > >Those shadows would seem to indicate a theatrical type stage >spot light higher up than your flash would have been. It also >would tie in with MarkF’s comment about a bright scene using >fill flash. After all you did say you were using iTTL-BL. In >that case if there was a bright spot light, then it could be >possible that the skin tones were illuminated sufficiently >that your shutter speed, aperture and ISO settings provide a >correct exposure. If you add flash on top of that, even at >fill flash levels you could potentially over-expose those >areas.
The shadow details are consistant with holding the camera in portrait orientation with the flash to the left. That makes the right side of their faces (from the photographer's perspective) fall in the flash shadow area. This is why I always shoot this type of shot with the camera in horizontal orientation, which makes the shadows fall behind the subjects, out of sight. Then, I crop to vertical later if that is what is best.
>I was shooting Ist photo sb-800 TTL-BL > >2 Photo was SB - 900 TTL-BL
In that case I have no idea why you got such overexposure. TTL-BL normally underexposes with the flash power being set mostly by the distance to the subject, not by the monitor preflash return. The flash power is set to add just a small amount of fill. Your photos look look more like examples of regular TTL than TTL-BL.
>Russ, I’m surprised to see you include shutter speed for I was >under the impression that for the most part shutter speed has >no affect on flash output.
You are correct. The shutter, when in normal sync mode, does not affect flash power. However, the shutter does affect the ambient contribution, and ambient always adds to the exposure on the subject when using Regular TTL. So, if the ambient is strong, and the flash power is fixed, and you change the distance or the shutter, the exposure of the subject will change. This is why you should always make sure the shutter speed is fast enough to eliminate most of the ambient on the subject (I recommend -2 to -3 stops underexposure of the ambient). Then, additional changes of the shutter have no effect on the exposure of the subject.
I agree, if you have time!!! I am shooting Graduates flying across the floor every 30 seconds or less. In fact my SB-900 stopped working because of over heating during one Graduation!!! This is the 5th Graduation I have shot and most class sizes are between 300-500 students.
Bob, Do you still have more graduations to shoot? If so, I agree with Barry, use your flash in manual, that's my preferred shooting style. I also set my camera's meter to manual & use matrix metering. Best of luck.
Vlad, Sure, Instead of placing my camera in Program Mode, Shutter, or Aperture Priority I use Manual Mode. In Manual Mode you set the shutter speed and aperture. Now, I don't use Manual Mode 100% of the time, it just depends on the shooting situation. I prefer to use Matrix Metering which reads the whole frame and then sets the exposure based on brightness, contrast, color, and composition. I hope I answered your question.
>Photos appear hot over exposed in TTL? I am shooting w/ a >Nikon D3 > >(Graduation handshakes) inside w/ camera set manual @ F 5.6 / >125th shutter > >speed / ISO 800. Meter indicates approx. 1.5 - 2 stops under >exposed? > >I am expecting the SB- 900 to deliver TTL with perfect >exposure. However, > >the photos are over exposed? Could it be the flash or the >camera? > >Thanks, > >Bob
In reading through this thread, I noticed that you were using TTL-BL mode. This is probably your error. TTL-BL is only for fill flash when the ambient is bright and matched well to the flash color (like outdoors in daylight). You should only use TTL-BL when you want the ambient to be primary on the subject. Also, for TTL-BL to work properly, the camera metering has to be centered, so one of the auto exposure modes is usually best. If the meter is not centered, you never know what you are going to get, so using camera Manual as you described, coupled with TTL-BL is totally wrong.
You almost never want the ambient to be primary on the subject indoors, so you should be using Regular TTL mode, which will make the flash primary on the subject. Then, you should set the camera in Manual mode and the aperture and shutter to underexpose by two to three stops to eliminate the ambient contribution on the subject. This will allow the flash metering system to control the exposure by adjusting the power of the flash to make the subject a standard brightness.
Then, there is the black clothing issue. Black clothing will cause weak reflected energy from the monitor preflash, and that will increase the flash power to try to make the reflected energy a standard value. That will often cause overexposure. When you said you metered off the subjects face, I think you meant you metered the camera off the subjects face, but this will do absolutely nothing to the flash power. To meter for the flash, you have to use FV Lock to fire the preflashes with the subject's face in the center. Then, the power that the flash calculates will be right for the face, and it will be locked in, so you can recompose to place the subject's face where you want it.
Also, ISO 800 is very high for shooting flash, and it lets in way too much ambient which causes color shifts on the subject, and sometimes the flash cannot go to low enough power and you get overexposure. It is much better to use ISO400.
>(Graduation handshakes) inside w/ camera set manual @ F 5.6 / >125th shutter > >speed / ISO 800. Meter indicates approx. 1.5 - 2 stops under >exposed?
Flash photography is a weak point of mine, so if you don’t mind I would like to express my thoughts to hopefully help you while advancing my own understanding and skills.
For me, you are leaving out a pertinent piece of information when discussing flash photography, and that's subject distance. In fact you could have left out the shutter speed for that really is only for the ambient light, not the flash. It would also be helpful to include a sample image with the EXIF data intact to give a better idea of the camera settings and conditions instead of getting information piece meal.
Your including the information that the meter indicates a 1.5 to 2-stop under exposure tells us more than the shutter speed does, and that the ambient light should have provide minimal illumination to the subject and the flash should be the main light source. As such I would think it would have been best to use iTTL not iTTL-BL.
Your impression that the images came out looking overexposed certainly indicates something went askew.
Yeah, I’m glad to see that Russell chimed in on this. If you haven’t already, you should check out his web site on the Nikon CLS System. There is a wealth of information there that would have helped with the setup for your circumstance.
I typed up my reply this morning, but then realized I was running late for a luncheon appointment and ran out of the house before I posted it. But I’m glad to see my thoughts were on the right track. I also thought ISO 800 was a bit high, but not being that experienced and not knowing the subject distance I was hesitant to comment upon it.
As to your query to Russ I’m sure he’ll respond, but to my understanding with flash it would depend on the subject distance. The SB900 at 1/8th power and zoomed to 135mm, the flash would have a guide number of about 59. At ISO 800 and f/5.6 you would have a subject distance of about 30 feet. Of course that’s assuming you're using direct flash with no modifiers. At least I hope I calculated all that correctly!!
edited to add:
Actually I find iTTl works fairly well. I chuckled a bit when I was reading this thread because I have two examples of images I shot at my clubs last Obedience Trials of some of the winners. There is two different shots at different shutter speeds that show how it controls the ambient, but has little affect on the flash output.
If you want to see them they’re on my Pbase site here and here.