[Big Bob]

Trying to figure out which to use or both. If you're using the onboard flash and you want for example +1 stop, should you set the flash exp comp, or the camera exp comp. Within the camera is there any connection between the two. Would a combination of both ever be advisable - say in a fill flash situation?

Any light you can shed (no pun intended) on this would be greatly appreciated.

[Adam]

The flash compensation will affect the actual intensity of the flash and normally doesn't allow you to make very big adjustments (i.e. probably only +1 stop or -2 stops). The camera compensation will use the lens's aperture and/or ISO to control exposure.

Depending on your lens and its maximum aperture, you may need to use both to get the proper exposure or depth of field. The flash compensation also works well if you want to intentionally blow the highlights, i.e. in product photos

[AdrianM]

The answer depends on the light relationship you want between between subject and background. The flash will light the foreground object (presumably, your subject), so you may want to adjust the flash power for that. For example, I would normally use a -1/3EV compensation when I am taking photos of birds to avoid white highlights in feathers blowing out. Speaking simplistically, the camera exposure bias setting decides what the background looks like - whether I want it darker or brighter than what the eye would see; and the flash decides the subject.

[Big Bob]

The answer depends on the light relationship you want between between subject and background. The flash will light the foreground object (presumably, your subject), so you may want to adjust the flash power for that. For example, I would normally use a -1/3EV compensation when I am taking photos of birds to avoid white highlights in feathers blowing out. Speaking simplistically, the camera exposure bias setting decides what the background looks like - whether I want it darker or brighter than what the eye would see; and the flash decides the subject.

AdrianM thank you for your reply. It hit nail right on the head. My question derived from my use of the flash to fill in in back light contrasty conditions. I was getting pretty good results with the flash except in a few images the subject still needed some additional exposure. So its sounds like I should boost the flash a tad as the background is exposed properly. Again thanks.

[AdrianM]

Thanks for your comments Bob. Here is a sample shot that I took this morning. The camera settings were basically set in Manual mode to a slight underexposure using whole frame metering, and the flash also set to slightly underexpose by using PTTLHSS with a -1/3EV bias. By using PTTL, the flash finds the right exposure for the subject, but I find that it can over-power whites in these birds so drop the flash power back by 1/3EV.

Pentax K-3, Sigma 500 f4.5 APO DG EX, Pentax Hd 1.4x Rear Converter, Metz 58AF-2 flash, Better Beamer FX-3, tripod


M (manual) mode, ISO 640, 1/1000th, f9 (corrected for RC), flash in PTTLHSS mode at -1/3EV