Over exposure with an SB 910

Discussion in 'Nikon' started by joseph_mcdonald, May 11, 2015.

  1. Shooting with a D600 and an SB 910, matrix, program mode, single point auto focus. I'm using the 24-85 kit lens that came with it.
    The range on the speedlight said <2ft. - 30, or thereabouts. Indoors, not too bright ambient light.
    My subjects were 5-6 feet away and their faces were way over-exposed.
    Forgive me for sounding naive but I thought these newer cameras were "smarter" than my old F4 or even my F100. I flipped down the diffuser and it got a little better. Can someone here see something obvious that I am missing?
     
  2. Hi Joseph, could you post an example? Without seeing the photos, I could make a guess. How far were the subjects from the background? Were they wearing dark clothing? What focal length were you shooting at? The reason I ask is because matrix metering exposes for the overall scene. If you subjects were far from the background, wearing dark clothes and/or their faces were the only light toned part of the picture, these instances could lead to the metering issues.
     
  3. This is what I'm talking about. I'll guess they were 6-8 feet from me.[​IMG]
     
  4. Which setting on the SB?
    It`s hard to believe that this results came from a TTL-BL setting... maybe from Manual or Auto mode.
    The EXIF says wide open (aperture priority) at 1/60... and there is a fooling deep black background (black dresses, dark blue carpet...). It could be the cause... but you`re shooting matrix so it should`t. Are the other shots right?
    I don`t have the 910 but previous models, and find them to be quite good on my D700.
     
  5. mm THis type of shot there only a few choices when using one (camera mounted) flash only, either the persons on the forground are exposed properly, or the background is exposed . in this case it is the background...
    If you want the ppl on the foreground exposed properly , you will need to spot meter , or center weighted, that way you camera understands better what you want..
    And if possible, move the flash "off Camera"" to the left or right and have it controlled by your buildin flash ( or possibly just the build in flash for this situation, since it is less powerfull..).
    Also bouncing the flash of the ceiling might give you much better exposure, because it alows the light to spread over the room.
     
  6. I think the girls cover too little of the overall scene for matrix to know how to expose it. I'm not sure Program mode is the best thing to use, either, if it wants to shoot wide open in this scenario. Use Aperture Priority.
     
  7. I am inclined to think the problem is exactly iTTL-BL - the background is quite well lit and basically balances quite well. And it seems in an attempt to balance this lighting, the actual subjects got this overexposed. I'd try this with the camera metering set to Centre-Weighted (which will switch the flash to 'normal' iTTL instead of iTTL-BL), and my guess is that things would come out just fine then. Possibly choose a slower shutterspeed and higher ISO (=shoot manual, if the shutterspeed can remain the default, use A mode) than you normally might to balance the natural light a bit more, but basically force the camera to expose the flash for your subject only, as CPM said.
     
  8. ShunCheung

    ShunCheung Administrator

    Definitely avoid the Program mode for flash photography; that mode limits your options for flash.
    The overexposed subjects (2 girls) and the harsh shadows suggest that it was direct, frontal flash. If the ceiling is not too high or dark, I would bounce the flash off the ceiling or back wall. If those options are not practical, I would use a bounce card. This type of direct flash rarely yields pleasing results.
    EXIF data show 24mm, f3.5, 1/60 sec and ISO 200. For these indoor situations, I would use a slower shutter speed such as 1/30 sec to increase the contribution of ambient light, while reducing the aperture to f5.6 or f8 to cut the contribution from the flash. Need to pay attention to subject movement at such slow shutter speeds, though. Keep in mind that a smaller aperture would cut contributions from all light sources, flash and ambient alike, but a slower shutter speed would only increase the contribution of ambient light. The speed of the flash is fractions of 1/1000 sec; as long as your shutter speed is the flash sync speed or slower, a faster or slower shutter speed does not affect the contribution from the flash.
     
  9. The predominance of black background is throwing the metering off. You'd probably get a similar result from the same scene without using flash, but just the ambient lighting.
    I'd switch to centre-weighted or spot metering for a subject like this, where the major area of the frame is a lot darker than the subject. Or use AA mode on the flash - much more consistent than I-TTL IMO.
    Incidentally the flash coverage doesn't seems to be matching the lens; the corners are quite dark. Check you haven't got the flash switched to manual zoom mode. You might also want to zoom in to get the subject(s) bigger in the frame and exclude a lot of that busy background. The camera could also have been turned to portrait orientation. That might have improved the exposure considerably as well.
     
  10. I'll try taking more the wife and kid inside (ambient background) and outside tonight (dark background) and try some of the settings recommended here.
    Thanks to all who have replied.
     
  11. The problem is that the subjects are out of focus. When the flash head is not bounced (i.e. in the straight ahead direction) Nikon's Creative Light System depends heavily on focus distance information to calculate flash output.

    The focus landed further away than your subjects so the camera system calculated flash output based on that further distance. I've seen this happen a number of times and always figured it's part of what the D means (distance) in 3D matrix metering.
     

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