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Existing internal processing and adjustment using RAW format?
- By Gilad Weil
- EOS Bodies
- 11 Replies
Hi 
As part of a vegetation monitoring program in nature reserves, I examine changes by using a time series of photos. I use a modified rebel i3, in which the internal IR filter has been removed (http://www.maxmax.com/ircameraconversions.htm). I use a series of external filets in order to sample in different wavelength. I use fixed WB, shutter speed and RAW format only.
I dont need a "good looking" picture - I need the original data with minimal Intervention of the camera.
But my question has to do with the image processing – since the results I get aren't good enough:
1.I am interested in the raw values of the radiation – Is there any additional processing in RAW format, such as balancing blue green and red (the sensor was double green detectors, any effect?), or adjustment in the case of saturation of the sensor?
2.Where can I find quantitative data (not picture) about the behavior of the sensor along the spectrum?
Thanks!
Gilad Weil
Remote Sensing,
Nature and Park Authority
As part of a vegetation monitoring program in nature reserves, I examine changes by using a time series of photos. I use a modified rebel i3, in which the internal IR filter has been removed (http://www.maxmax.com/ircameraconversions.htm). I use a series of external filets in order to sample in different wavelength. I use fixed WB, shutter speed and RAW format only.
I dont need a "good looking" picture - I need the original data with minimal Intervention of the camera.
But my question has to do with the image processing – since the results I get aren't good enough:
1.I am interested in the raw values of the radiation – Is there any additional processing in RAW format, such as balancing blue green and red (the sensor was double green detectors, any effect?), or adjustment in the case of saturation of the sensor?
2.Where can I find quantitative data (not picture) about the behavior of the sensor along the spectrum?
Thanks!
Gilad Weil
Remote Sensing,
Nature and Park Authority
How resistant are L lenses against the shocks/vibrations?
- By climber
- Canon Lenses
- 25 Replies
I don't mean if lens drops down on the floor. 
I mean how resistant are they against the shocks let say while driving on a really bad road. Assume that lenses are stored in a padded camera bag. Are those vibrations critical for any kind of glass displacement inside of lens?
I mean how resistant are they against the shocks let say while driving on a really bad road. Assume that lenses are stored in a padded camera bag. Are those vibrations critical for any kind of glass displacement inside of lens?50mm Coma Sigma Art vs Regular Sigma F1.4
- Canon Lenses
- 4 Replies
Had a rented 50 Art last weekend and did a quick coma comparison in the corner of a full frame 6D. Old on the left Art on the right. F1.4, F2, F2.8. Ignore the brightness differences as it's just different areas of the sky. I should have done them on the tracking mount instead or paid more attention to location but it really doesn't matter for this.
Most all the 50mm offerings are so bad at it. The Art I'd hoped was even better than it was. Even if at the same time it is far better than the others, minus the Zeiss and the more expensive Nikon. In a way it's a 1 stop boost in less coma. Though yeah it is going to be sharper anyway. But if I was shooting something with street lights near the corners or with stars, I'd probably feel the need to head to F2.8. And if I'm at F2.8 I just about may as well be using the old Sigma. It's softer but guessing I'd maybe sell it for $200, making the jump $750 and I'm not sure it is that much softer when we're talking far corners here anyway. Not sure why I had it in my head the F2.8 Art coma result is what F1.4 was going to be closer to. Lenstip made it seem close to that. Or well lenstip coma at F1.4 looks like my star test between F2 and F2.8 I guess.
Anyway, just an example for those looking at getting it for that reason, which is probably many.
Most all the 50mm offerings are so bad at it. The Art I'd hoped was even better than it was. Even if at the same time it is far better than the others, minus the Zeiss and the more expensive Nikon. In a way it's a 1 stop boost in less coma. Though yeah it is going to be sharper anyway. But if I was shooting something with street lights near the corners or with stars, I'd probably feel the need to head to F2.8. And if I'm at F2.8 I just about may as well be using the old Sigma. It's softer but guessing I'd maybe sell it for $200, making the jump $750 and I'm not sure it is that much softer when we're talking far corners here anyway. Not sure why I had it in my head the F2.8 Art coma result is what F1.4 was going to be closer to. Lenstip made it seem close to that. Or well lenstip coma at F1.4 looks like my star test between F2 and F2.8 I guess.
Anyway, just an example for those looking at getting it for that reason, which is probably many.
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