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I have been experimenting with bracketing my images, and I like to use raw format, so I can get more latitude when I need it. However, the dcraw program, which is used to convert raw files to something that Autopano Pro can handle, automatically adjusts the image to provide a good exposure! When I am not bracketing that is what I want, but when I am bracketing I don't want dcraw to undo my deliberate over- or under-exposure.
dcraw recently acquired a new switch, -W, which prevents this behavior. Thus, I can get bracketed TIFF files to feed to Autopano Pro by using this command line:
dcraw -w -W -T -4 *.RAW
-w means use the camera's white balance, -W means don't do exposure compensation, -T means output .TIFF files and -4 means 16 bits per color.
The problem with this procedure is that some of the EXIF data is lost. Apparently Autopano Pro is able to read some EXIF data from .RAW files that dcraw does not copy to .TIFF files. Therefore my request is that Autopano Pro allow me to change the command line used to invoke dcraw. For panoramas which include bracketing, I would add -W. Of course, the command line should be included in the .pano file.
Thank you,
John Sauter (John_Sauter@systemeyescomputerstore.com)
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Since you don't do any specific correction to your raw photos when batch saving using dcraw, why do you use dcraw separately at all? Do you feed those 16 bit tiffs to some hdr or *fuse program, and only then stitch, or do you feed them directly to APP?
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I use dcraw separately so I can suppress exposure compensation with -W. I feed the .TIFF files directly to Autopano Pro. I specified 16-bit .TIFF files so I can learn how to handle them in Autopano Pro.
John Sauter (John_Sauter@systemeyescomputerstore.com)
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hmm, I still dont understand why, why don't you just feed them to APP? Do you get better results when feeding APP 16bit tiff files than when using raw files?
I do use a raw converter but for two other reasons:
1- better quality using a dedicated raw converter than relying on APP's auto conversion
2- I usually run the files through tufuse which supports only tiff.
Since you dont do any special sharpening or other things in dcraw, and as far as I know (i tried on older versions of APP some time ago, but i generally dont feed APP raw files) APP uses dcraw but doesnt try to fix underexposed shots. Am I wrong about this?
ps. I wasnt satisfied with the result of running tufuse on raw files exactly because dcraw (tufuse calls dcraw to convert raw to tiff) tried to fix underexposed shots which ruined everything, i will try again some time with the -W option, thanks!
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I don't just feed the .RAW files to Autopano Pro because when it converts from .RAW is does exposure compensation. When I am bracketing I don't want exposure compensation. Although I have been experimenting with 16-bit color, that has nothing to do with my desire to avoid exposure compensation when processing .RAW files.
-W was added to dcraw quite recently. You may have to get the current version, at http://www.cybercom.net/~dcoffin/dcraw/.
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I just realised that what I thought was the color anchors changing my source images, it could have been as you said dcraw autocorrecting! hehehe, took me long enough :]
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So why isn't there already a way to modify the commandline for dcraw? It can't be that difficult. ;-)
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