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Better B&W JPGs using CHDK...

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Offline cristiano007

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Better B&W JPGs using CHDK...
« on: 30 / March / 2009, 16:22:17 »
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I posted this in the Flickr group and someone told me to post it here: According to many experts the Black & White option of many digital cameras is very flat and lifeless (I agree), almost everybody recommend to shoot in color (JPG or raw files) and then do a better conversion in your PC with different methods. Only some Leica and their poor sisters Panasonic (LX3, by instance) have an option for rich and strong B&W, callled Dynamic B&W. The Custom colors feature in my Canon compact are not enough to do this. What you think? Would be possible to do this with CHDK? I think it could be very interesting for many other users too...
« Last Edit: 30 / March / 2009, 16:25:33 by cristiano007 »
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Offline hotvedt

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Re: Better B&W JPGs using CHDK...
« Reply #1 on: 31 / March / 2009, 17:13:38 »
Maybe the custom curves feature can do this?
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Offline reyalp

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Re: Better B&W JPGs using CHDK...
« Reply #2 on: 06 / April / 2009, 16:04:19 »
Image processing should be done on the PC. If you start with raw, you can anything that could be done in CHDK, much faster and more flexibly.
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Offline jamoraquai

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Re: Better B&W JPGs using CHDK...
« Reply #3 on: 06 / September / 2009, 21:19:45 »
any update on this? i really hope this can be done using CHDK. my gf has an lx3 and i really like its dynamic b&w. i would really love to have that in my g7 also.:D
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Offline reyalp

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Re: Better B&W JPGs using CHDK...
« Reply #4 on: 06 / September / 2009, 22:21:59 »
Quote from: jamoraquai on 06 / September / 2009, 21:19:45
any update on this? i really hope this can be done using CHDK. my gf has an lx3 and i really like its dynamic b&w. i would really love to have that in my g7 also.:D
There's nothing to update. With the tools currently available to CHDK, it's a bad idea and it's not likely to happen in the foreseeable future. Until someone reverse engineers the DSP side of digic (progress so far: 0%), image processing belongs on the PC, not on the camera.

CHDK at the moment can only modify the raw buffer (before it is turned into a jpeg), it can't alter the jpeg process, or the jpeg after it has been created. The camera jpeg develop process (again, presumably with the help of the DSP stuff that is a magic black box to us) is designed to produce a color image. One could probably figure out how to modify the raw buffer to get the camera to produce a mostly black and white jpeg, but it's likely the quality would be less then you would get from converting a normal jpeg to B&W on your PC, and certainly less than you could get from doing the same to a RAW. Since processing on the ARM CPU is quite slow, doing B&W this way would probably not be a lot quicker than saving the RAW.

Bizarrely, the "My colors" option on my a540 offers sepia but not plain B&W. Color accent does a passable B&W if you select a gray as the color. Now that I think about it, tracking down the code that handles these options might be a place to start for someone is interested in hacking the colors of jpeg output.
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Offline jamoraquai

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Re: Better B&W JPGs using CHDK...
« Reply #5 on: 06 / September / 2009, 22:38:59 »
Quote from: reyalp on 06 / September / 2009, 22:21:59
There's nothing to update. With the tools currently available to CHDK, it's a bad idea and it's not likely to happen in the foreseeable future. Until someone reverse engineers the DSP side of digic (progress so far: 0%), image processing belongs on the PC, not on the camera.

CHDK at the moment can only modify the raw buffer (before it is turned into a jpeg), it can't alter the jpeg process, or the jpeg after it has been created. The camera jpeg develop process (again, presumably with the help of the DSP stuff that is a magic black box to us) is designed to produce a color image. One could probably figure out how to modify the raw buffer to get the camera to produce a mostly black and white jpeg, but it's likely the quality would be less then you would get from converting a normal jpeg to B&W on your PC, and certainly less than you could get from doing the same to a RAW. Since processing on the ARM CPU is quite slow, doing B&W this way would probably not be a lot quicker than saving the RAW.

Bizarrely, the "My colors" option on my a540 offers sepia but not plain B&W. Color accent does a passable B&W if you select a gray as the color. Now that I think about it, tracking down the code that handles these options might be a place to start for someone is interested in hacking the colors of jpeg output.

thanks for the reply reyalp. appreciate it. hopefully someone would be interested in looking into hacking colors of the jpeg output as you have mentioned above.:)
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Offline bongo_bingo

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Re: Better B&W JPGs using CHDK...
« Reply #6 on: 07 / September / 2009, 01:06:13 »
I think it's way better to do this conversion in pp, even because you cannot add valid color to a bw image.

For example look at this picture http://pamdavi.deviantart.com/art/Pieghe-T-C-M-133624259 , then look at this http://pamdavi.deviantart.com/art/The-Timeline-T-C-M-133819373

Sorry to post links to my works, but it's way to get the idea of what I'm meaning
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Offline jamoraquai

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Re: Better B&W JPGs using CHDK...
« Reply #7 on: 07 / September / 2009, 04:32:46 »
yup. you're right bongo_bingo. thanks for the reply. it's just that it's more convenient to people like me who don't pp often to have a good looking b&w image right out of the camera without the need to pp.
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Offline drewm1980

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Re: Better B&W JPGs using CHDK...
« Reply #8 on: 07 / July / 2010, 02:48:32 »
Hi Reyalp-

Would it be more feasible to convert the live display to B+W?  I'm happy converting to B+W in pp, but it would be very nice to have an idea what the black and white photos will look like while I am shooting, so I can adjust white balance, exposure, etc. appropriately.

Even on the S90, Canon treats shooting in B+W like a gimmicky toy.  If you put the camera into B+W mode, not only do they disable the nice 2D white balance adjustment, they disable RAW.

Cheers,
Drew
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