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mercphoto
Jul-17-2005, 02:30 PM
I'm having flash metering issues. Canon 20D, 580EX, ETTL-2 mode, Time-priority and high-speed sync turned on. FEC set to -2/3. During daylight this combination works very well. As the sunlight falls it still works well, but it is always giving me a trouble with this particular guy.

Good shot:
http://mercphoto.smugmug.com/photos/28744734-M.jpg

Bad shot:
http://mercphoto.smugmug.com/photos/28744538-M.jpg

Is the problem the fact this shot has so much blue in it? Any way to solve this?
Shay Stephens
Jul-17-2005, 03:21 PM
The flash is just too strong. Auto flash control can be problematic in low light. Manual mode may give you more consistent results. I have to use manual when doing weddings in low light.


The problem in the second photo is that the flash is providing more than just fill, it is competing with and up close, overpowering the ambient illumination.

An option might be to feather the light or use a flag or barn doors to prevent light from hitting as much of the ground as you see in the second photo. You might consider a snoot or grid attachment to spot light the driver only.
mercphoto
Jul-18-2005, 10:32 AM
The flash is just too strong. Auto flash control can be problematic in low light. Manual mode may give you more consistent results. I have to use manual when doing weddings in low light.
What is most strange is how it overexposes only on this rider, and I was wondering if the large amount of blue in the scene was possibly throwing off the flash exposure metering.

I think I might have to go manual on the flash exposure for night racing, as you suggest. I almost have to go manual focus anyway. When I fire a shot, is there anyway to tell how strong the flash fired? If so, then I could make a test shot, and then set the flash on manual at that power setting.

Also, if memory serves, that histrogram isn't blown out, so if I was shooting RAW, its possible that shot could have been saved?
tmlphoto
Jul-18-2005, 02:02 PM
The OE shot can be saved with a not so drastic levels adjustment. Just bring up the shadow slider and then tweak the midtones down a little. The adjustments don't have to be very much to get a decent result. You could also uses curves. Autolevels will work OK with this shot as well.