CRW or CR2 in actual bona fide Canon format

tuffshed

« on: 16 / February / 2009, 15:40:19 »

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I'm new to using CHDK, but not new to digital photography or use of raw so bear with me, and maybe this is a question rather than a feature request, but here goes :

Can we have the output of the CRW or CR2 files be formated exactly like (or close enough) to those actually generated by Canon firmware?

I found out, to my surprise that the CRW and CR2 files generated by CHDK and my A640 cannot be read by bona fide genuine Canon image processors like DPP. I also find out there is missing info in the CHDK generated files (like white balance and EXIF info).

Is there a reason why the CHDK versions of CRW or CR2 are different from versions generated from Canon firmware? Why would you not want the file format to be exactly the same, or as close as possible, so that it appears to every peice of Canon support software to be generated from a Canon camera?

At very least, CHDK should not generate files with the CRW or CR2 extension as this tends to fool people into thinking it is actually in CRW or CR2 format, perhaps the extension should be CHDK.

I don't believe it is a standard if there are TWO incompatible versions. I would think that the Canon format is the de-facto standard.

What important peice of information am I missing here?

Thanks,
- Mike (aka tuffshed)

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fvdk

146
Ixus 70 1.01b / 1.02a & Powershot A590is 1.01b

Re: CRW or CR2 in actual bona fide Canon format

« Reply #1 on: 16 / February / 2009, 16:35:14 »

Quote from: tuffshed on 16 / February / 2009, 15:40:19

What important peice of information am I missing here?

Thanks,
- Mike (aka tuffshed)

Just about everything that is written here http://chdk.setepontos.com/index.php/board,15.0.html

Frans

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whim

2022
A495/590/620/630 ixus70/115/220/230/300/870 S95

Re: CRW or CR2 in actual bona fide Canon format

« Reply #2 on: 16 / February / 2009, 16:55:20 »

It will simply not help to try and make a 'compatible' CRW for , say, A640 - DPP will refuse to read it anyway,
because Canon only allows pix from cams that they equip with raw shooting ...

CHDK only offers the CRW CR2 extensions because the Canon USB protocol flatly refuses to transport anything but
a short list of extensions, as a concession to people who need to use the USB to offload their pics ...

IMHO you can in general assume that CHDK follows standards wherever feasible, this is just one of those cases where it
is not ...

Oh, and about "badpixel.lua": there's a wiki page about it http://chdk.wikia.com/wiki/Badpixel_removal

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Microfunguy

4037

Re: CRW or CR2 in actual bona fide Canon format

« Reply #3 on: 16 / February / 2009, 17:32:50 »

Quote from: tuffshed on 16 / February / 2009, 15:40:19

perhaps the extension should be CHDK.

Using SDM and WIA-Loader you can do exactly that and automatically convert them to DNG files :-

http://stereo.jpn.org/eng/sdm/upload.htm

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tuffshed

Re: CRW or CR2 in actual bona fide Canon format

« Reply #4 on: 16 / February / 2009, 18:02:05 »

Quote

It will simply not help to try and make a 'compatible' CRW for , say, A640 - DPP will refuse to read it anyway,
because Canon only allows pix from cams that they equip with raw shooting ...

I'm not sure what you are saying...

I don't own a Canon camera that supports raw, but I've installed a version of DPP which I downloaded from the official Canon website, then downloaded an example raw CRW from a Canon camera from the web and DPP could read it just fine. I don't know if my version of DPP (3.5.1) support every Canon raw enabled cameras, but I'm sure it supports more than one. This way you would have Canon supported and blessed utilities for free, with upgrades and support by Canon (I saw several updates of DPP, all free to download)

I'm asking for CHDK to support a version of CRW that is output by a Canon camera that does support raw, you choose, I would think there are several Canon cameras, if not all, that support the same format with minor differences (the name of the model of the camera)

I haven't heard a technical reason why the CHDK version of CRW cannot resemble the CRW of the Canon (you choose the model) camera. Is there such a reason that CHDK firmware cannot output the same format ?

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reyalp

12598

Re: CRW or CR2 in actual bona fide Canon format

« Reply #5 on: 16 / February / 2009, 18:14:32 »

What does CRW/CR2 provide that DNG doesn't ?

Quote from: tuffshed on 16 / February / 2009, 18:02:05

I haven't heard a technical reason why the CHDK version of CRW cannot resemble the CRW of the Canon (you choose the model) camera. Is there such a reason that CHDK firmware cannot output the same format ?

Depends. For example, professional canon cameras typically use 12 or 14 bits per pixel. Most Canon P&S are 10. So it isn't necessarily possible to write a correct CRW without additional processing.

Aside from that, supporting additional poorly documented, proprietary file formats is a hassle. They contain a bunch of meta data that is specific to each camera, and getting the correct values for cameras that never supported CRW could be a lot of work.

FWIW, CRW format documenation can be found at http://www.sno.phy.queensu.ca/~phil/exiftool/canon_raw.html

My personal opinion is that attempting to add it to CHDK would be a huge waste of effort. DNG is widely supported and open.

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