Trouble with Nikon TTL flash

[Michael Bailey]

I've been waiting years to be able to take advantage of through-the-lens flash. Got by in the meantime with trusty Vivitar 283's and 285's, but always thought TTL would be the foolproof path to consistent flash exposure. But now that I'm using the Nikon D-300 and D-700 with SB-800 flashes, TTL leaves me flummoxed. If anything, TTL exposures are even more off the mark than basic automatic.

I've consulted forums for answers, but when I read someone present a problem similar to mine, the responses seem along the lines of: "I get great results with my system! Just set the exposure to minus one and seven-eights and make sure you're in a room that measures 17x26 meters with a three meter high white ceiling, and it's perfect!" I assumed then that the problem lay in earlier model digital sensors that prevented operation of a system originally designed for film.

Not to give up without a fight, last week I bought Joe McNally's book, The Hot Shoe Chronicles. But even he concedes that there are aspects of the system that just don't add up. (Minus-One on the camera combined with Plus-One on the flash doesn't really equal zero. Ought to, but doesn't. He concedes that it's up to us to work out the solution for each situation.)

I've searched the camera and flash manuals, which is, believe me, no minor task, and they tell me what's supposed to happen. But it just doesn't.

So, can anyone recommend a comprehensive guide to using this system for consistent exposure? Most of the guides I've looked at read more like extended product testimonials. The text will tell you what the system is capable of, then the neighboring photo will show you a dramatic scene that may or may not back up the point. Now that I think of it, I've never seen a book print a "contact sheet", or digital equivalent, showing a consecutive series of plain-vanilla real-life flash photos that display reasonably accurate exposure. Is consistency with basic flash-on-camera/camera-bracket even possible, or should I give up and go back to "A"?

Short of that, can anybody tell me how the three (count them, three) exposure compensation settings relate to one another? The camera has basic +/- exposure control. Then it has the same just for flash. Then the flash itself has it, too.

Lost and Confused

[gardenvalley]

I've been waiting years to be able to take advantage of through-the-lens flash. Got by in the meantime with trusty Vivitar 283's and 285's, but always thought TTL would be the foolproof path to consistent flash exposure. But now that I'm using the Nikon D-300 and D-700 with SB-800 flashes, TTL leaves me flummoxed. If anything, TTL exposures are even more off the mark than basic automatic.

I've consulted forums for answers, but when I read someone present a problem similar to mine, the responses seem along the lines of: "I get great results with my system! Just set the exposure to minus one and seven-eights and make sure you're in a room that measures 17x26 meters with a three meter high white ceiling, and it's perfect!" I assumed then that the problem lay in earlier model digital sensors that prevented operation of a system originally designed for film.

Not to give up without a fight, last week I bought Joe McNally's book, The Hot Shoe Chronicles. But even he concedes that there are aspects of the system that just don't add up. (Minus-One on the camera combined with Plus-One on the flash doesn't really equal zero. Ought to, but doesn't. He concedes that it's up to us to work out the solution for each situation.)

I've searched the camera and flash manuals, which is, believe me, no minor task, and they tell me what's supposed to happen. But it just doesn't.

So, can anyone recommend a comprehensive guide to using this system for consistent exposure? Most of the guides I've looked at read more like extended product testimonials. The text will tell you what the system is capable of, then the neighboring photo will show you a dramatic scene that may or may not back up the point. Now that I think of it, I've never seen a book print a "contact sheet", or digital equivalent, showing a consecutive series of plain-vanilla real-life flash photos that display reasonably accurate exposure. Is consistency with basic flash-on-camera/camera-bracket even possible, or should I give up and go back to "A"?

Short of that, can anybody tell me how the three (count them, three) exposure compensation settings relate to one another? The camera has basic +/- exposure control. Then it has the same just for flash. Then the flash itself has it, too.

Lost and Confused

[gardenvalley]

Exposure compensation on the camera affects the total exposure, ambient and flash. Flash exposure compensation on the camera affects only the flash whether on-board or speedlight. Flash exposure compensation on the speedlight affects only the flash output. TTL flash is a great tool but is not infallible. For consistent exposure it may be necessary to use the flash in manual but in a fast moving situation this may not be possible. TTL will get an acceptable shot most of the time but it`s best to keep an eye on the screen, review and adjust as required.

[Geoff Wittig]

Depends on what you're shooting, ambient lighting conditions, etc. etc.
I'm using Canon, which if anything is less consistent and reliable than Nikon when it comes to TTL flash control, but with a bit of practice it all starts to come together. There are a couple of principles that always apply. TTL flash works just like your camera's TTL meter, meaning it tries to make everything 18% grey, so if your subject is a dark-haired person with tan skin in a navy blue coat, he'll come out overexposed. One of the points McNally makes in his book is that if the camera's meter 'sees' even a slightly different perspective from one frame to the next, the TTL exposure will vary as it attempts to render everything middletone. That may explain the inconsistent results you're getting.

For what it's worth, If ambient light is important I'll first meter and set exposure manually before turning on the flash, deliberately determining whether I want the ambient exposure to be light or dark. Then I'll take a shot with flash, and adjust using flash exposure compensation as needed depending on results. I rarely need more than two shots to get it where I want it. Exposure compensation for the camera only matters if you're in a program exposure mode. I try to avoid it because I forget where I have it set too easily. I definitely suggest setting exposure compensation at the camera, not on the flash, if only to avoid "double compensating" if you set both by mistake.

I tend to use two off-camera flashes on lightstands with Canon's ST-E2 controlling them from the camera, which lets me alter the ratio between the flashes at will. The huge convenience offsets the occasional inconsistency. Nikon has something similar, their 'commander' unit, which is even better because it allows you to set three different flash ratios rather than two with Canon's gadget.

There are several books out on Nikon's "creative lighting system" for flash. But you'll probably learn more taking lots of photos with a cooperative subject (a patient model or stuffed animal) and seeing what happens with various settings.

Hope that helps.

[MarkL]

Read everything here: http://nikonclspracticalguide.blogspot.com/ this will tell you exactly what the camera/flash is doing which helps understand what has happened when it screws up. In particular read about TTL and TTL-BL and their differences and also read about FV lock, FP-high sync too.

Shooting TTL with auto iso on and in aperture priority mode things can get quite complicated quite quickly!

Nikon's flash system does have it's quirks (eg. the effect of exposure compensation) but it is the best out there. Often you do have to resort to chimping and playing the compensation though, it's a big ask for it to deal with every situation perfectly.

Post come examples with full exif if you can. The exif tells you a lot about what the flash did and how it was set so we can help you troubleshoot.

[Michael Bailey]

Thank you all for your replies. I will definitely take a closer look at the link MarkL mentions. It looks on first glance to be very promising.     MB