Technical question about camera specs

[Tim Schulz]

Hi all,

I am interested in the technical specifications for cameras in general, and for the Canon 50D in particular.

My current interest is in the spectral response curves for the red, green, and blue filters in the Canon 50D, but I’m also interested in learning more about other technical aspects of the sensor.

[bruce norikane]

Hi Tim,

Interesting question.  I’ve never seen much technical data on specific camera sensors.  Some of the sensor vendors publish technical data sheets, but I’ve never seen one.  I think Canon makes the 50D sensor, for Canon’s exclusive use, so they probably don’t publish anything on that sensor.  

Some people have deduced quite a bit from analyzing images, especially raw files.

The best known sensor database is the DXOmark website. DXOmark attempts  to compare different sensors by normalizing raw file data.  DXOmark:
http://www.dxomark.com/

Many of the technical review sites use Norman Koren’s Imatest software to analyze image files:
http://www.imatest.com/home
Imatest analyzes images, so the whole camera – lens, sensor, processing – is tested.  But with careful test setups, it can be used to analyze some sensor information.

Raw file format information is available in the open source for dcraw:
http://www.cybercom.net/~dcoffin/dcraw/

There are some tools that build ICC profiles for cameras, but I’ve never really followed them.  The camera profiles may provide some detail on color response curves.  The standard ICC profile tools may be useful with these profiles. DDIsoftware (they make the excellent Qimage printing software) sells camera profiles.  They may be dcraw compatible, so you might be able to extract more information from them with modified software.

http://www.ddisoftware.com/shopping/index.html#cameraq

Hope this helps – bnn

[bruce norikane]

I ran across this Canon white paper on their CMOS sensor today. It’s high level, but there’s some technical information in it:

http://media.the-digital-picture.com/Information/Canon-Full-Frame-CMOS-White-Paper.pdf

Also Emil Martinec wrote a substantial piece on Canon 20D sensor noise.

[Tim Schulz]

Bruce,

Thanks for the pointers.

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