Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Canon eos R vs. R6

accessories CMOS astrophotography
  • Please log in to reply
2 replies to this topic

#1 max.reiter

max.reiter

    Lift Off

  • -----
  • topic starter
  • Posts: 1
  • Joined: 16 Sep 2020

Posted 16 September 2020 - 12:10 PM

I am in the wake of buying a new Camera. The primery use will be daytime photography for which both are more than good enough.

But the secondary use will be with a star tracker (star adventurer) and a telephoto lens. In the future also with a telescope and an more professional mount.

Right now i am using a panasonic dmc g7 16Mp micro four thirds sensor

Now i am facing a dilema
My problem is:
The eos R has about 30Mp resolution using an "older" chip from the eos 5D Mark IV (2016)

The new eos R6 has about 20Mp resolution using a newer chip from the eos 1D X Mark III

The newer sensor will most likely have a better noise performance

The other problem is pixel size vs. pixel count

Pros of bigger pixels
-better low light performance (probabilitiy of getting enough photons to register a signal is higher)
-better thermal noise performance

Pros of higher pixel count
-better at retaining high resolution while cropping (good because i often need to crop with telephoto lenses of max 400mm)

What do you think? Should i get the older sensor with the higher pixel count or the newer one with, even for a full frame camera, low pixel count?

#2 bobzeq25

bobzeq25

    ISS

  • *****
  • Posts: 21,059
  • Joined: 27 Oct 2014

Posted 16 September 2020 - 12:42 PM

I am in the wake of buying a new Camera. The primery use will be daytime photography for which both are more than good enough.

But the secondary use will be with a star tracker (star adventurer) and a telephoto lens. In the future also with a telescope and an more professional mount.

Right now i am using a panasonic dmc g7 16Mp micro four thirds sensor

Now i am facing a dilema
My problem is:
The eos R has about 30Mp resolution using an "older" chip from the eos 5D Mark IV (2016)

The new eos R6 has about 20Mp resolution using a newer chip from the eos 1D X Mark III

The newer sensor will most likely have a better noise performance

The other problem is pixel size vs. pixel count

Pros of bigger pixels
-better low light performance (probabilitiy of getting enough photons to register a signal is higher)
-better thermal noise performance

Pros of higher pixel count
-better at retaining high resolution while cropping (good because i often need to crop with telephoto lenses of max 400mm)

What do you think? Should i get the older sensor with the higher pixel count or the newer one with, even for a full frame camera, low pixel count?

Calculate the image scale, the number of arc sec covered by a pixel.  It's the key parameter.

 

Divide the focal length (of any optics you're considering) by 200.  Divide the pixel size by that.

 

The lower (numerical) value will have a worse signal to noise ratio, and potentially higher resolution, if a number of things go right.  The larger value will have better signal to noise ratio, no matter what.

 

Short focal length optics will generally have image scales of 2, or numerically higher.  In that range, a lower numerical value is better.  As you go from 2 down to 1, it's a tradeoff, personal judgment.

 

MP are irrelevant.   If you can get read noise at different ISOs (https://www.photonstophotos.net/), the characteristic of little variance of read noise with ISO (the buzzword is "ISOless"), is desirable.  Lets you shoot at low ISOs, with better dynamic range.  A big deal.

 

I have a number of scopes/cameras, generally am between 1.0 and 2.7.  Higher numerical values than 2.7 with short camera lenses.  My D5500 is ISOless.  With my scopes and my good mount, I shoot at 200.  With my camera tracker, 400 because the tracking isn't as good.

 

The key thing is total imaging time.  More equals better signal to noise ratio, more dim stuff.  My rule of thumb is one hour minimum, 2 is better, 4 good.

 

Shoot more subs.  <smile>


Edited by bobzeq25, 16 September 2020 - 12:49 PM.

  • George N likes this

#3 George N

George N

    Fly Me to the Moon

  • *****
  • Posts: 5,851
  • Joined: 19 May 2006
  • Loc: Binghamton & Indian Lake NY

Posted 18 September 2020 - 09:51 AM

I recently went thru the same 'exercise' but with the R6 vs the Ra - about the same price, but the R6 was (still is??) not available in August - when I needed the camera for 2 weeks at my dark-sky cabin, so I went with the Ra. BTW - Canonisti seem to conclude that the R and Ra will remain in production well into 2021 - but the R is already reduced in price.

 

Here is a review of the R5 vs the R6 for 'astro' (guess nobody wants to review the older stuff): https://petapixel.co...iso-comparison/

 

Actually -- for me a 'commercial' camera is just a back-up to my SBIG STL-6303e CCD and a FLI ProLine CCD (that I don't own, but often use). I just want something for wide-field (up to 400mm focal length) - and for those times I can't haul a laptop along - like quickie trips to Cherry Springs where I'll mostly be doing 'visual'.

 

Note -- I was also concerned with all the 'chatter' a month ago about the new R5 and R6 overheating while doing vidio ( I had an old 70D DSLR die from vid overheating ). There were rumors that Canon would have to 're-call' both the 5 and 6 to re-work them. That plus the good results people are getting from the Ra - pushed me in that direction. I also purchased one of Canon's new RF lenses (note the adapter to connect older lenses to the new mirrorless cameras is out-of-stock EVERYWHERE). I got this - a great lens: https://www.digitalc...3-is-usm-review

 

This camera will even grab hand-held star-scapes -- under full moon! Nothing to write-home about -- but I've never had a DSLR do that!

 

My first mistake -- everything came out blue -- Blue -- BLUE -- too blue! What? I ordered a Ha sensitive camera and put a narrow-band filter on it!! Looking closer -- when you set the camera to "P", or "M" (manual) of "B" (bulb) -- for some odd reason the factory-settings changes the white balance from "natural - daytime outdoors" to "indoors tungsten" -- and assumes it has to boost the 'blue'. You have to manually go into the menu and set the correct white ballance. I'm hoping that I can find software that will automate conversion of the CW3 files to TIF -- and at the same time convert the white balance back normal.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: accessories, CMOS, astrophotography



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics