Auto Bracketing

[Sepiana]

Hi everyone,

Be warned! This is a pretty dumb question!

I was trying to use the AEB in the Rebel XT. I was going to use "1 stop gap". Then, I saw some sources on the Web saying to use 2-stop gaps or even half-stop.

What's your opinion on this? Should one vary the stops according to the situation? Is there an optimal setting?

The reason for this question? I've just downloaded the free demo for Photomatix and was trying to take 3 photos at different exposures to make an HDR image.

Thanks for your responses in advance.

[JulieM]

Sepiana,

For your first tests, I suggest doing -2, 0, +2 or -1, 0, +1. Once you've done a few like that you may wish to abandon auto-bracket in favor of doing the exposure set-up yourself. For HDR, I don't use auto-bracket at all because my xTI can only do 3 exposures and I prefer taking 5. (I may not necessarily use all 5, but I've got them if I need them.) I think the best results come from doing an exposure check of the brightest part of the scene, noting the exposure settings the camera chooses then doing the same for the darkest part of the scene. Take your exposures (3, 5, 7 or whatever number you wish) using these as the end points. I use manual exposure (you could use AV), setting the aperture and letting the camera tell me what shutter speeds to use. I've heard that your darkest exposure should have no blown highlights and your lightest exposure should have no plugged shadows. All that said, I don't think HDR is an exact science at all. Your results are going to vary widely depending on the dynamic range of the scene. It is all about experimentation.

I can't wait to see your stuff!

[TonyW]

I agree with Julie although I haven't found 1 stop bracketing to be worth the effort. IMHO you need at least 2 and often more (I can do 2 via autobracketing but usually have to go manual or use exposure compensation to get a wider exposure range or use ACR/Lightroom to increase/decrease the exposure more than I can get via autobracketing).

Tony

[Sepiana]

Thanks a lot, Julie and Tony!

This was easy to understand. I copied and pasted your posts for future reference. I'll try the 1 and 2 stop bracketing so I can see the difference.

Julie, when I get something going, I'll post it. Just don't hold your breath! My husband bought the Rebel in 8/2005 and only now I'm getting deeply interested in using it. But better late than never!