Nikon Z6

[MarkS]

I'm now the proud owner of a Nikon Z6 mirrorless camera (body only).

I'll be doing some testing on it from an astrophotography point of view.  Especially to compare it against the Sony A7S.

But I won't modify this one until I'm certain it has no serious weakness affecting astrophotogreaphy e.g. the notorious PDAF striping.

Mark

[Carole]

What is the advantage of a mirrorless camera?  Sorry to ask but I don't know much about the technical aspects.  Also what is PDAF Striping?

Are you hoping this will work as well as the A7S without some of the A7S drawbacks that you have found?

Carole

[ApophisAstros]

If things go swimmingly with the Nikon , would you consider selling the Sony.?
Roger

[NoelC]

Looks very interesting Mark
Will follow your exploration with great interest.
What sensor is it using?  I notice it has 24.5M pixels, does that reduce the potential sensitivity by half, or can you reclaim that simply by changing the resolution setting?  I assume the Low Pass filter option is switchable.  Is there any history with this processor? Did you consider the D810?

Noel

[MarkS]

Answering some questions:

The advantage of mirrorless for me is that on a fast f-ratio telescope there is no vignetting and diffuse light from the edges and sides of the mirror box.  That's why I would not consider something like the D810.

Mirrorless cameras have special autofocus pixels, in this case phase detect AF (PDAF).  This can cause single pixel wide stripes in images under certain conditions.

I'm certainly hoping the Z6 will overcome some of the weaknesses of the A7S but I will still keep the A7S because the large pixels and low noise (read and thermal) make it well suited to the long focal length slow focal ratio of the Celestron C11. 

The sensor is a back-side-illuminated Sony sensor specially built for Nikon.  I believe it might have a higher QE (quantum efficiency) than the Sony A7S which will make it better for long exposure imaging but it definitely won't surpass the A7S for low-light video.

The anti-alias filter is not switchable.  In fact it has an advantage by producing better star colours.  The disadvantageous smoothing effect is easily removed by deconvolution.

Mark

[MarkS]

If you are interested in my ongoing testing of the Nikon Z6 (warts and all) then follow this thread:
https://www.cloudynights.com/topic/670370-nikon-z6-testing

The main wart at present is the PDAF banding.

Mark

[The Thing]

Very interesting stuff on the CN forum. It's worth having this info in the back of your mind when considering a new camera purchase even if you don't follow it completely. Which I am not at the moment but it will happen sometime. Thanks Mark.