CMOS: Player One Poseidon M

[PRejto (Peter)]

I am completely new to this type of camera and I've barely had a chance to test it, however, my very early results are confusing.



Question: At gain zero, where the dynamic range is highest, how would one expect the CMOS chip to compare in sensitivity to a standard CCD chip, say the Sony 964 chip? More, less, equal?


My preliminary results suggest that my camera is less sensitive - and on the same target, same OTA, it appears that I need longer subs to get close to the CCD. If I increase the gain to 125 for sure the sensitivity increases but the well depth plunges, and even at this setting I would say the image is better with the Sony CCD.



So, what is all the "talk" about greater sensitivity and shorter exposures about? Or, is there something I'm not doing correctly, or is my camera possibly defective?


Thanks!
Peter

[PRejto (Peter)]

I'm going to answer my own question thanks to a reply from Terry Platt at SX.

He pointed out that the well depth of the 694 Sony chip is basically half that of the 571 CMOS chip. Consequently the images from the 571 chip will look dimmer as the electrons are spread over a much larger dynamic range. Thus, the effective gain of the 571 is about 50% of the 694 chip with smaller wells.

This seems obvious in retrospect,, but it wasn't to me before asking!

Peter

SX seemingly has a 571 CMOS camera in testing....

[Nikolas (Nik)]

I have read both posts and am none the wiser, too technical for me.

[ChrisD (Chris)]

Originally Posted by PRejto

I'm going to answer my own question thanks to a reply from Terry Platt at SX.

He pointed out that the well depth of the 694 Sony chip is basically half that of the 571 CMOS chip. Consequently the images from the 571 chip will look dimmer as the electrons are spread over a much larger dynamic range. Thus, the effective gain of the 571 is about 50% of the 694 chip with smaller wells.

This seems obvious in retrospect,, but it wasn't to me before asking!

Peter

SX seemingly has a 571 CMOS camera in testing....

Also the pixel size of the 694 is 4.54µm while the 571 is 3.76µm. Approx 30% larger pixel collects more electrons and dumps them into that smaller well.

Chris