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Creating high dynamic range images with Adobe Photoshop
Rather than describe what HDR imaging is and why its useful, I will direct to the following information:
Paul Devevec's research
Wikipedia entry
Adobe Photoshop (as of CS2) gives you the ability to construct your own high dynamic range images from a series of low dynamic range photographs. To do this, I recommend a tripod and cable release. First set your camera to Av (Aperture Priority) mode (with the aperture of choice for your shot) and meter on the scene, this will give you a baseline exposure to work off of. Then switch to M (manual).
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LDR at 0ev
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LDR at -1ev
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LDR at +1ev
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Now take a series of shots starting at an ev level that doesn't result in clipping your highlights and ending at an ev level such that the darkest areas of your images have sufficient detail.
I usually like to shoot RAW, so the first thing I do is select all the images in Bridge, open them up in RAW and synchronize all their settings. Make sure the 'auto' checkbox is NOT checked and make sure their white balances are consistent.
Launch Photoshop and go to File->Automate->Merge to HDR. I prefer doing this from Photoshop rather than Bridge because if you do it from Photoshop, you can check off the box that tells it to 'auto align' the images.
Photoshop will go off and start chugging away creating your HDR image. When finished you will have a 32bit image. Note that most filters and operations aren't available in 32bit mode, so if you want to do any fancy editing you will have to convert to either 16-bit or 8-bit. When you do this, Photoshop brings up a dialog asking you how you want to pack all that extra information in your HDR image into a low dynamic range (LDR) image. This problem is called tone mapping, and there are many algorithms out there. Photoshop has four options. Each has its own use, 'Local Adaptation' is perhaps the most flexible as it allows you to specify the tone curve but it is also the most difficult to use and get good results out of.
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Manually twiddled
exposure/gamma
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Highlight compression
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Equalize histogram
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Local adaptation (with manually set tone curve)
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Once you've converted to 16/8 bit, proceed with your normal workflow. For this image, personally I like the highlight compression algorithm better (though local adaptation does fairly well but requires more input from the user), however I have played with other HDR images where equalize histogram works better. In the end however, if you want to maximize the results you get from your conversion you'll want to use local adaptation and manually twiddle your tone curve until you get something that looks good. Remember that there really is no 'correct' answer for HDR->LDR tonemapping; it is up to your artistic vision.
If you want to play with this file, you can download the OpenEXR version here. This particular test image has over 14 stops of information.
Also, if you want to play around with different tone mapping algorihtms, check out exrtools by Billy Biggs.
This the final version with a little bit of post processing applied after LDR conversion.
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