Nikon SB 900 Problem

[wedding photographer]

I have noticed the following problem at a wedding with my Nikon SB 900 flash:

- If I take 3-4 pictures immediately after each other the individual pictures are inconsistently exposed. For example, the first one is dark, the second one is lighter, the third dark again and the forth one is lighter again. The difference is not that bad so I cannot compensate in PP but still weird!

If I take the pictures without the flash all the pictures are evenly exposed so the camera works perfectly...

Has anybody experienced this?

[drg]

I have noticed the following problem at a wedding with my Nikon SB 900 flash:

- If I take 3-4 pictures immediately after each other the individual pictures are inconsistently exposed. For example, the first one is dark, the second one is lighter, the third dark again and the forth one is lighter again. The difference is not that bad so I cannot compensate in PP but still weird!

If I take the pictures without the flash all the pictures are evenly exposed so the camera works perfectly...

Has anybody experienced this?

The problem you describe sounds typically like the flash has not recycled fully or it is being overridden when it isn't ready or should be firing.

The flash doesn't need to fire at 'full' power for every photo depending upon the circumstances. If the problem is that are trying to fire the camera and flash with the flash at full power for every shot at the max frames per second it most likely will not work properly.

Depending upon how frequently your are trying to fire the flash, unless you are using an external battery pack, it will require longer between shots. Rechargeable batteries of different types will work differently. If you are depending upon splash and spray technique to get a shot, it is iffy at best. This is a wedding, not a sporting event, though the former is often a lot more difficult as there is a greater degree of spontaneity in the 'action' at a wedding.

Some Nikon Bodies control the SB-900 a bit differently than others or don't fully exploit various modes. There is in the end no true ACE (Always Correct Exposure) with flash no matter what. There will be some clinkers. The Nikon iTTL is d*** good when used with the right combo of diffusers and other bounce type light controls.

As as starting point to further refine an answer to this issue:

Do you understand the the difference between Auto Exposure settings and TTL settings and Manual settings as a starting point with the Nikon Flash system?

Which Nikon body, what settings, and has the flash fully recycled?

Finally, do you have the Flash Unit mounted on the camera's hot shoe or is it on and extension cord/bracket?

[Franglais]

I get this sometimes towards the end of a long shoot. I think that the batteries are running out of juice. My SB800 will fire even if it's not fully charged, but the green light blinks if it ran out of power before completing the shot.

I always use high-capacity NiMh batteries which I charge up just before going out. And if it's important (wedding - I don't do that many) - I take along a second flash and change over halfway through the event.

[Grandpaw]

I have a D90 with the SB800 flash and I tried to make mine replicate what you are saying. I placed my flash on TTL and was using A-priority while taking some pictures for my test. I placed my camera on spot meter and tried taking a picture of something light and then moved the camera spot off the light area and moved it just a little to the left with almost the same composition,but the lighting was very different in the two shots. Could it be that you are using your spot meter and having the meter spot on different lighter or darker spots? When I used matrix metering they were both the same lighting, Jeff

[livin4lax09]

could your camera be set for exposure bracketing, using different apertures?

[mattbikeboy]

There are a few of things I have noticed with SB-900 flashes:

1) SB-900s don't recycle fully when the batteries go down -- so they loose output even after a bit of time. So pick up some new rechargable batteries (but never buy the grey Lenmar 2700mah).

2) SB-900s make a weird quiet pop sound when the batteries only have one or two flashes left

3) SB900s loose all control once they die and need servicing. If you've smelled the wonderful burning plastic smell -- it needs servicing. It'll will still fire, but it will not be consistent at all -- even with new batteries.

4) Watch where you are metering, you'll get crazy results when using the same settings to shoot close-ups of a bride in a white dress and then shoot the groom in a black tuxedo. TTL is very good but can be fooled by dark clothing. I found that it's quickest to roll the flash to backlight mode when shooting people in dark clothes and then back to regular TTL for everything else. There are many ways in camera and on flash to control output, but one counter clockwise click on the wheel is fast and takes just enough power out to be useful. Also heavy spray tans and airbrush makeup fools it as well -- I have no idea why though.

5) If you are shooting with a bracket and a sync cord -- make sure it is a Nikon. Off brands are horrible (most of the time). Even a Nikon unit will wear out in 4-6 months with heavy use. You can test by putting the flash on the hot shoe directly and see if it solves your problem.

So my suggestion is to try new batteries first and if that doesn't fix it -- it probably needs servicing. Nikon is pretty quick with flash services and you should be get it back within two weeks (even without NPS membership).

Good luck,
mc