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CHDK dng profile generator project

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Offline vit40

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Re: CHDK dng profile generator project
« Reply #20 on: 29 / January / 2011, 02:52:47 »
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Hi nonno

I don't have a profile for S5IS, but I can make it. Just read the first part of described procedure and send me a jpg and dng pair. If something is not clear, ask. Some steps in the procedure are different than people usually do when taking photos, because whole procedure is very specific for this program, so just do as described, don't do anything different, trying to "improve" the procedure, and everything will be ok

Vit
« Last Edit: 29 / January / 2011, 11:14:14 by vit40 »
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Offline nonno

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Re: CHDK dng profile generator project
« Reply #21 on: 29 / January / 2011, 10:19:08 »
thank you very much for your helpfulness. Right now the weather is really foggy, but as soon as I can I'll take the shots, following exactly your instructions, and I'll send you them!!! (Maybe you should remove your email address from the forum or it will be filled by spam)
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Offline quid

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Re: CHDK dng profile generator project
« Reply #22 on: 30 / January / 2011, 12:28:55 »
Can you generate profile for SX130? I hope this picture is sunny enough - it's hard here to get sunny day in this time of year :)

http://www.megaupload.com/?d=8OAYNHPI

Do you think we can use this method with generated CRW and calculations like in DNG4PS to create better 3x3 matrix for camera?
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Offline vit40

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Re: CHDK dng profile generator project
« Reply #23 on: 31 / January / 2011, 09:00:38 »
Hi, here is test crw

http://www.megaupload.com/?d=OVWEEOHR

I also included a profile for SX200 that I made for eapl, just changed camera name in exif tag to SX 130 IS, so you can try it in the meantime. I tried it with your dng and colors are very similar as in jpeg from the camera, just that jpeg has more contrast, probably because of different processing in the camera for this scene

About white balance, it would probably need some corrections (for SX130 or maybe for SX200 also), as displayed color temperature is too high. If you have some old dngs, made in fine weather, you can try and see how much correction is needed (temperature and tint) to get close to daylight preset (5500K, tint +10), so I can correct it (I must do it manually - can't be calculated with this method)
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Offline quid

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Re: CHDK dng profile generator project
« Reply #24 on: 31 / January / 2011, 17:05:15 »
I've uploaded developed jpeg.
http://www.megaupload.com/?d=OEFYZG6Z

I don't have any old photos with fine weather (new camera, even newer CHDK port :)), so we have to wait until I will be able to take a new one.
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Offline aepl

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Re: CHDK dng profile generator project
« Reply #25 on: 01 / February / 2011, 06:11:46 »
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Offline vit40

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Re: CHDK dng profile generator project
« Reply #26 on: 01 / February / 2011, 12:01:21 »
quid,

Could you develop another jpeg, just with ISO set to 100 instead of 400, and all other settings the same. Processing in SX130 is different than in camera I calibrated so far (including SX200) - in ISO 400 there is a kind of strong color bluring (besides less sharpening, like in other cameras). I didn't spot it in the first set of two jpegs that you sent (first was ISO 80 and the second was ISO 400). With this jpeg, I'm affraid that profile won't be accurate enough in the shadow region

Can you also try developing test crw in wide zoom position. You don't have to send jpegs, I'm just interested is resulting picture deformed and with brightened corners (because of built-in correction for the lens) or not

Vit 
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Offline vit40

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Re: CHDK dng profile generator project
« Reply #27 on: 01 / February / 2011, 12:27:50 »
Aepl,

in case you select Embedded profile, ACR will use default "Adobe tone curve", that IS different than tone curve in the camera or in the profile I generated (as you noted in DNG profile editor). It is generic tone curve for Adobe standard profiles for all cameras. Default settings for that profile are exposure = 0 and blacks = 5. That's one of the reasons for the difference in brightness. Second reason is that all CHDK dngs have baseline exposure tag -0.5, which originated from some older Power shot cameras, but every camera model has slightly different mettering, so this value is probably slightly wrong for most new cameras.

Also, depending on the scene, digic can change tone curve or saturation for in-camera processing, resulting in different picture than ACR with this profile. If you have i-Contrast on, it will also probably brighten shadows - you can simulate that using fill light slider and/or raising brightness slider

Bit depth for SX200 and SX130 is 12 bit, while it was 10 bit for older CHDK cameras. You can get various information about dng using command prompt utility exiftool (there are probably other similar tools too)

In case you can make some daylight pictures on sunny weather, or have some older dngs, taken in fine weather, check what is average color temperature and tint for those pictures shown in ACR, when you select this profile and WB as shot (if you had AWB selected in the camera), so we can correct this information in the profile if needed

Vit


« Last Edit: 01 / February / 2011, 12:29:42 by vit40 »
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Offline quid

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Re: CHDK dng profile generator project
« Reply #28 on: 01 / February / 2011, 14:45:09 »
I've made more pictures and I think best results are on ISO200 with lowest setting on Sharpness slider. There are three files in archive: IMG_1210.JPG - ISO100, lowest Sharpness, IMG_1211.JPG - test CRW on wide, IMG_1212.JPG - ISO 200, lowest Sharpness.
http://www.megaupload.com/?d=NLDAFXX6

I think there may be slight brightening of corners on test image developed on wide, but it's impossible to say, because of heavy distortion correction - most of gray frame is cropped out. Amount of processing is better visible on this picture (CRW+JPG):
http://www.megaupload.com/?d=NYZH03WJ
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Offline aepl

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Re: CHDK dng profile generator project
« Reply #29 on: 01 / February / 2011, 19:15:01 »
Hi Vit40.

You said:
"Bit depth for SX200 and SX130 is 12 bit, while it was 10 bit for older CHDK cameras. You can get various information about dng using command prompt utility exiftool (there are probably other similar tools too)"

I am confused. I executed Exiftool and I can't understand the meaning of these values:

---- IFD0 ----
Bits Per Sample                 : 8 8 8
Samples Per Pixel              : 3

---- SubIFD ----
Bits Per Sample                 : 12
Samples Per Pixel              : 1

Thanks in advance.
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