Quote:
Originally Posted by Peter Ward
I often ask myself of anything I read on the net "Does that seem reasonable", with a touch of Cal Sagan's "extraordinary claims require extraordinary evidence"
Point Grey's "measured" QE for the Sony IX674 is 70% at 385nm....amazing !!! since that beats the very best (and very expensive...they fly similar sensors on Hubble) E2V back illuminated CCD's currently available. I'd suggest Point grey got absolute vs relative QE's confused....
One wonders if they used a rain gauge  |
Peter, its not just Point Grey who have measured Sony CCD performance.
Did a quick search and found that Apogee, Carl Zeiss, FLI and Photometrics have also published absolute QE curves for the ICX285 that are similar to the Point Grey data (not identical though, so not copies). The (previous generation) ICX285 has an absolute QE of at least 60% over much of the visible band according to all sources - it should not be surprising that the newer Sony chips are even better - they have been in this game for a fair while.
http://www.ccd.com/ascent_disc_qecurves.html
http://www.zeiss.de/C1256D18002CC306/0/4E9EF8C9122BBA9CC1257149005146D1/$file/48-0065_e.pdf
http://www.flicamera.com/spec_sheets/MLx285.pdf
http://www.photometrics.com/products/datasheets/HQ2.pdf
However, this discussion on Sony chips really misses the point of David's thread - the new cameras that are appearing are exceptional. Back illuminated 20mp+ chips promise higher QE than affordable existing chips and they will have enough small pixels that they can be adapted to any chosen scope and seeing conditions by way of binning. Provided the manufacturers make them in mono form, there could be some very interesting astro cameras available in the near future. Regards ray