Canon EOS R6 mark II analysis for night/astro imaging

The thin horizontal and vertical central lines are normal. What is less normal are the two other thin lines above and below the horizontal axis, most probably due to the dual pixel structure of the sensor.

But it has no visible impact on the images. At least, nobody has been able to show any evidence.

Thanks for this, it's very interesting. Do you know any particular reason for the effects (both read noise and the "flattening" of the FFT at ISO 200?

Also, the ISO 100 results surprise me. I would expect the read noise to be more or less constant across the ISO ranges. I thought that read noise happened before the ISO gains were applied (so constant number of electrons, then multiplied at higher ISO's).

Regards,
Dan

DanInSoCal wrote:

Thanks for this, it's very interesting. Do you know any particular reason for the effects (both read noise and the "flattening" of the FFT at ISO 200?

No idea, this is how Canon’s engineers have programmed the DigicX processing of the signal…

Also, the ISO 100 results surprise me. I would expect the read noise to be more or less constant across the ISO ranges. I thought that read noise happened before the ISO gains were applied (so constant number of electrons, then multiplied at higher ISO's).

Noise adds up at several places :

- 1 - before amplification : it is therefore amplified the same way as the signal

- 2 - after amplification : it is not amplified, but just added to the signal (+ previous noise)

B_R_C wrote:

fred 76 wrote:

The thin horizontal and vertical central lines are normal. What is less normal are the two other thin lines above and below the horizontal axis, most probably due to the dual pixel structure of the sensor.

But it has no visible impact on the images. At least, nobody has been able to show any evidence.

It is a satellite...Very common

Ah ah ah

Bigger wrote:

I would expect this to cause very sharp stars to appear slightly oblong along the long axis of the image, but maybe not enough to be noticeable?

For that I should (wait for clear sky) take some photos using a telescope on a good tracking mount, then any astrophoto software will show the out of roundness of the stars. Easy but the weather is not great here !