It's official: Canon XL2 announced

Aaron Koolen · August 5th, 2004, 04:11 PM

Andre, if I understand you, that's along the lines I was thinking. Regardless of bit depth of the A/D, Assuming all CCD's and everything else is equal, the brightest white will be the biggest number on each A/D correct? This seems to make perfect sense to me as a programmer, but I'm not up with all the optical stuff.

Aaron

Jeff Donald · August 5th, 2004, 05:29 PM

Andre, I'm not following what your saying. Are you saying 8 bit and 16 bit image files have the same dynamic range?

Andre De Clercq · August 6th, 2004, 03:37 AM

Yes Jeff. The non adaptive CCD dynamic range is the range between the highest signal level (limited by a certain amount of distortion- "white clip" in video)and the lowest signal level (limitted by a certain amount of unwanted vs wanted signals- noise, glare..in cams ). This figure is seldon higher than 45 db in consumer camcorders. Maybe there is a confusion about how well a scene's dynamic range (80db and more) is being "packed"into the limited camers range. This subjective compression
performance is like I wrote (knee processing, gamma, ..) bitdepth dependent.

Jeff Donald · August 6th, 2004, 04:45 AM

Even before processing the 16 bit file would contain more levels of gray (greater dynamic range) that are discernible to the eye than an 8 bit file.

Andre De Clercq · August 6th, 2004, 07:28 AM

Here http://www.fillfactory.com/htm/techn...df/oeepe99.pdf (PDF) is some info on CCD (and CMOS) dynamic range. IMEC is a Belgian micro electronics research center where I used to be a member of the scientific advisory commitee for several years.

Jeff Donald · August 6th, 2004, 10:31 AM

Thanks Andre, I'll look that over after classes this afternoon. You may be interested in Norman Koren site and his discussion on tonality and dynamic range.

Andre De Clercq · August 6th, 2004, 02:23 PM

Interesting article. Although dynamic range is a well defined ratio, the " hidden dynamic range" approach is a good idea that kinf of explains what I wrote before: using high bitdepths allows manipulating (mainly expand) "hidden" parts in the analog signal.

August 5th, 2004, 04:11 PM	#181
Aaron Koolen Trustee Join Date: Apr 2002 Location: Auckland, New Zealand Posts: 1,727	Andre, if I understand you, that's along the lines I was thinking. Regardless of bit depth of the A/D, Assuming all CCD's and everything else is equal, the brightest white will be the biggest number on each A/D correct? This seems to make perfect sense to me as a programmer, but I'm not up with all the optical stuff. Aaron __________________ My Website Meat Free Media

August 5th, 2004, 05:29 PM	#182
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Andre, I'm not following what your saying. Are you saying 8 bit and 16 bit image files have the same dynamic range? __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

August 6th, 2004, 04:45 AM	#184
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Even before processing the 16 bit file would contain more levels of gray (greater dynamic range) that are discernible to the eye than an 8 bit file. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

August 6th, 2004, 10:31 AM	#186
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Thanks Andre, I'll look that over after classes this afternoon. You may be interested in Norman Koren site and his discussion on tonality and dynamic range. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

August 6th, 2004, 03:37 AM	#183
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Yes Jeff. The non adaptive CCD dynamic range is the range between the highest signal level (limited by a certain amount of distortion- "white clip" in video)and the lowest signal level (limitted by a certain amount of unwanted vs wanted signals- noise, glare..in cams ). This figure is seldon higher than 45 db in consumer camcorders. Maybe there is a confusion about how well a scene's dynamic range (80db and more) is being "packed"into the limited camers range. This subjective compression performance is like I wrote (knee processing, gamma, ..) bitdepth dependent.

August 6th, 2004, 07:28 AM	#185
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Here http://www.fillfactory.com/htm/techn...df/oeepe99.pdf (PDF) is some info on CCD (and CMOS) dynamic range. IMEC is a Belgian micro electronics research center where I used to be a member of the scientific advisory commitee for several years.

August 6th, 2004, 02:23 PM	#187
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Interesting article. Although dynamic range is a well defined ratio, the " hidden dynamic range" approach is a good idea that kinf of explains what I wrote before: using high bitdepths allows manipulating (mainly expand) "hidden" parts in the analog signal.