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Old 03-03-2013, 08:04 PM
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Peter Ward
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Peter Ward is offline
 
Join Date: Dec 2007
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Quote:
Originally Posted by Shiraz View Post
Thanks Peter

Larger pixel sensors, eg 14u-20u do however have massive dynamic ranges compared to 4um-5um offerings. ..90 db or more.

yes, but we are not discussing that class of chip here - bit of a red herring.

I think there there is a visible hallmark to tiny well sizes (small pixels): as many of the images taken by these devices show nearly all stars as saturated to white as it is tricky to keep those tiny wells from overflowing.

Now I am confused. If you are saying that the icx694 will show nearly all saturated stars then you must also be implying that the ST8300 cameras that you sell* will show the same - after all, the KAF8300 CCDs (well depth 25,500) have only a little more well depth than the icx694 (20,000). There are enough fine images out there from 8300s to show that these CCDs do not necessarily have this problem, so there is no reason to expect that the icx694 will have it either....

regards Ray
I'd honestly say my pedaling KAF based devices is a sideline...and I do try to keep any commercial biases out of any postings...that said..

I'm very much a user of Astro-imaging gear with KAF8300, KAF16803 and ICX694 senors (plus a number of Canon DSLR's) all being in my personal arsenal.

My KAF8300 does indeed saturate very quickly... but I'd not call 25% better performance a "little" improvement over the ICX694.

A boost in QE, for example, by 25%, is obvious when you look at the raw data.

I also think Sony's noise figures are a little rubbery...clever correlation filters that also scrub photon liberated electrons can easily make noise look good at the expense of subtle signal.

Also can you, or someone, point me to a SONY ICX694 data sheet with absolute QE?...I can only find 3rd party specs...which I frankly don't trust.

The only method I've read about...apart from deep cooling...that keeps thermal electrons in the background is "Skipper" CCD technology...sadly not commercially available as far as I am aware.

I suppose what I am still saying, when it comes to pixels, is: bigger = better.

The downside is, bigger (matching optical systems) often cost a whole lot more....
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