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Old 31-01-2009, 05:32 PM
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CometGuy is offline
Join Date: Feb 2005
Location: Brisbane
Posts: 942

>> Roger, your correct, the Sony chip has about twice the QE

As I also stated 2 years ago I doubted the claim of 60% Quantum Efficiency for the Sony ICX453 (as used in various cameras like the QHY8 and Nikon D70, etc.). Where does this figure originally actually come from ?

If Canon sensors have a peak sensitivity of 35-40% and Sony sensors are at 60% there should be a huge difference in sensitivity that should be obvious in astrophotography. But lets look at some actual comparisions:

******** Comparision1 - Christian Buil's D70 vs 10D ***************:

Look at the graph "Nikon D70/Canon 10D relative spectral response at the same ISO". Note you have to multiply the Nikon graph by 2.98/2.41 to compensate for difference in GAIN. But the final outcome is the the D70 has very slightly higher Quantum Efficiency. Of course the 10D is several generations old now..

******** Comparision2 - Wayne Cosshall's D200 vs 350D ***************

Not the ICX453, but similiar CCD technology. I asked Wayne Cosshall who was near Geelong at the time to perform near simultaneous equal exposures with his 350D and D200 using the same lens at the same FL/aperture (Tamron 18-200 on both cameras). The Canon was clearly more sensitive than the Nikon. I'd be happy to post raw files if you doubt me (and if Mike will allow me).

******** Comparision3 - Chuck Vaughns 20Da vs Orion Starshoot Pro ***************

NGC891 - Starshoot pro 1170mm focal length, 200mm aperture, 260min exposure

NGC891 - 20Da 1180mm focal length, 155mm aperture, 260min exposure

Even taking into account extra light loss in the mirror system, the Starshoot Pro is working at an advantage (don't forget it is also cooled). The 20D shot shows as much detail and limiting magnitude is very similiar.


From the evidence I've seen either the 60% QE claims for the Sony CCD's are exagerated or Christian's values for the Canon sensors are too low.

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