Faint amp glow in an ASI2600MM Pro

Christian Bennich:
Hi All

I have recently made the switch to N.I.N.A. - and in that process also rebuilt my DARK library. 
When I looked over my new 300 sec. master dark made with N.I.N.A. I noticed a, what I believe is a very faint amp glow on the right-hand side of the image. 
I thought it was a light leak - check all my other master darks, and notice the same on all of them - growing clearer as the exposure time increased and mostly visible in the stacked final master dark. 
Made sure that I test in a completely dark room, with something covering that camera etc. to make sure that there is NO light coming into the camera.

I have the same thing in my ASI2600MM, Christian.  I sent photos to ZWO and they said it's normal.  (Still looks like amp glow to me, though!)  With flats, it honestly doesn't affect processed images.

Greg

Christian Bennich:
Hi All

I have recently made the switch to N.I.N.A. - and in that process also rebuilt my DARK library. 
When I looked over my new 300 sec. master dark made with N.I.N.A. I noticed a, what I believe is a very faint amp glow on the right-hand side of the image. 
I thought it was a light leak - check all my other master darks, and notice the same on all of them - growing clearer as the exposure time increased and mostly visible in the stacked final master dark. 
Made sure that I test in a completely dark room, with something covering that camera etc. to make sure that there is NO light coming into the camera.

I have the same thing in my ASI2600MM, Christian.  I sent photos to ZWO and they said it's normal.  (Still looks like amp glow to me, though!)  With flats, it honestly doesn't affect processed images.

Greg

Don't you mean "with darks" ?

Well, as you will need darks anyway to fight developping bad pixels, you should not care at all. This simply proves the point that the no-amp-glow is purely marketing argument. Those "amp-glow-free" camera are good cameras, but you will always be better off with darks, and the whole rack of calibration files.

Christian Bennich:
Hi All

I have recently made the switch to N.I.N.A. - and in that process also rebuilt my DARK library. 
When I looked over my new 300 sec. master dark made with N.I.N.A. I noticed a, what I believe is a very faint amp glow on the right-hand side of the image. 
I thought it was a light leak - check all my other master darks, and notice the same on all of them - growing clearer as the exposure time increased and mostly visible in the stacked final master dark. 
Made sure that I test in a completely dark room, with something covering that camera etc. to make sure that there is NO light coming into the camera.

I have the same thing in my ASI2600MM, Christian.  I sent photos to ZWO and they said it's normal.  (Still looks like amp glow to me, though!)  With flats, it honestly doesn't affect processed images.

Greg

@CingStars, Awesome that you actually sent images to ZWO to get their input 👍

I just checked my 300sec GAIN 100 Master and I can confirm the same. There are two areas on the right side and a constant on the lower edge. However, it is extremely low. I am right between ZWO promised ZERO Glow and it is not ZERO  VS it is sooo minimal, that it could be considred as ZERO.

In reality, I never even noticed until you mentioned it, so I agree with ZWO that it can be ignored.

I just checked my Darks and at 300s I have the same effect there. I also checked my dark 30s and 120s but it doesn't show in them.

Hi Christian,
I just checked all the 300s darks Ive captured for my 2600MM - I might be one of the lucky ones, but there is so sign of amp glow in the darks at all.

Here is a (normalised) master dark.


Don't forget that your screen shots are of a normalised dark, so anything even a few bits brighter than total black will be stretched to look much brighter than it really is. If you look at the average brightness in your dark, it's about the same as the amp glow, so the amp glow will be swamped by the background noise of the sensor.

Try opening the dark without normalising it, and check the histogram - measure the brightness value in the amp glow regions, it will be very close to 0, 0, 0.

As others have said, the impact will be immeasurably small if your lights are well calibrated.

Need to test my IMX571 then [non ZWO] to see if i have the same issue or not, thank you.

I began with a 294mc so I learned to calibrate because you absolutely have to…. I have the 2600mc and the 2600mm and I still calibrate because you Need to.

Yep. Normal. Part of what makes it show up so noticeably is how the calibration frames are stretched for preview. Because the sensor is quite low noise, many stretching algorithms will do a good job of bringing up that amp glow with an autostretch of sorts, when it is actually so faint that you likely wouldn’t have noticed it in an uncalibrated stack anyhow.

Attached is a 50% JPG 100% quality compressed preview of a 600s 100g -10°C masterdark from my 2600MM Pro. You can see similar amp glow on the right-hand side, and you can also see two other extreme characteristics of this sensor: some blooming around certain pixels, and a hint of vertical banding. All of this stuff is so faint that it is virtually irrelevant to the image anyhow, but nice all the same to have it represented in calibration frames. I’d wager if even a hint of light snuck in to the calibration frames a lot of this stuff wouldn’t turn up in a typical auto-stretch, and folks probably frequently miss how easy it is for that to happen.

So if all cameras must show amp glow even very slightly and must be corrected with dark frames, then what camera can be the best? It sounds no CMOS camera matched CCD in regard of free amp glow maybe?!!!