Nikon D7500 sensor parameters

[ppeake]

Using the new selector, it wants some info on the sensor (Camera Gain).
Not being able to find anything for the D7500 via Google, I used the BasicCCDParameters script to determine the characteristics.

The numbers work, but then again, virtually any random number seems to work ok for the subframe selector, and the pop-ups are not terribly informative.

Anyway ... back on track. Just wondering if the numbers that I obtained look believable:

Gain: 0.091 e/ADU
Readout Noise: 1.181 e
Dark Current: 0.005 e/sec
Full Well Capacity: 1484.083 e

Not sure that I really understand these well enough to be certain myself.

[sharkmelley]

You didn't mention what ISO you used.

So it's difficult to know if the numbers make sense or not (since they vary according to ISO).

Mark

[ppeake]

Yes, should have mentioned: ISO 3200

[sharpie78]

I used to use a canon DSLR and at ISO800 ;
gain : 0.27 e/ADU
Readout Noise : 2.8 e
Dark Current : 0.002 e/sec (diy cooler)
I cant remember the full well capacity

I'd say your figures look reasonable for the high ISO that you're using.

.....sidenote.....if you are guiding and can do 5 minute or more subs....reduce your ISO and expose longer. Aim for the main peak of the histogram of your exposures to be in the 20-40% area (1/3 of the way from the left)

[ppeake]

I am guiding, but with a 300mm lens, so exposure time is still rather short.
The D7500 actually behaves rather well at relatively high ISO.

[sharpie78]

If it's behaving well, stick with it then mate. 
I'm only going by the results I got with my EOS450D and our cameras obviously have different chips plus we're using different optics. If you read Jerry Lodrigus' book  - DSLR Astrophotography, there is an explanation on why lower ISO settings sometimes yield better results but I certainly couldn't repeat it to you verbatim.
I spent hours upon hours measuring sensor characteristics when I built a cooler for my DSLR, wanted to see if it was having any effect on noise etc. Very tedious but I learnt a lot in the process.