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Old 19-02-2013, 09:56 PM
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Peter Ward
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Peter Ward is offline
 
Join Date: Dec 2007
Location: The Shire
Posts: 8,090
There is a great deal of mis-understanding when it comes to low noise, QE and dynamic range of CCD's.

The new Sony chip is not bad, but for Sony (or anyone else) to call it a 16bit system is a joke.

Well depth is about 20k e-. Read noise 7e- hence the very best dynamic range you can get is about 2,800 levels.

16 bits of data = 65,536 levels.

So our Sony sensor is a little more than 10 bits. Resolve any finer, and you are simply resolving noise.

QE is quoted as 77%. Again where did this get pulled from???

Someone please show me this on the OEM Sony data sheet. (thanks, I have a copy, mine only shows relative QE )

Frankly this is amazing for a 4.5 micron pixel... hence I'd treat it with a grain of salt....thinking of salt (and pepper)

I have long suspected Sony bleed charge to get their sensors to look so clean (Lord knows I've has enough conversations with Terry Platt at SX over the years on this Chestnut )

But having looked at examples of the Sony ICX694ALG with narrow-band, I am left wondering "what happened to the shadow detail"??

I'd say little or none is their (Sony) hallmark..by the way, it is very hard to pick a thermal electron from one that arrived from the sky...

I have a a Sony ICX694ALG chipped camera. Works fine for planetary/solar, in fact great...but it does posterize...making me wonder about the sad 10 bit range...

But for touring the dim-dark-deep-sky, give me a noisy, thumping great American 400-cubic-inch-QE CCD any day.

Just my 2 cents worth.....
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