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

To bin or not to bin? That is the question.

  • Please log in to reply
26 replies to this topic

#26 freestar8n

freestar8n

    Vendor - MetaGuide

  • *****
  • Vendors
  • Posts: 8824
  • Joined: 12 Oct 2007

Posted 10 October 2019 - 03:38 AM

Quite right, and I often do that. Its just that one of the big benefits of binnng, as originally raised, was to reduce file sizes and processing time, and these benefits are not realised with downsampling. Its a different beast.

 

Im not complaining though, just more hard drives!

Yes - with cmos or very low noise ccd's there is little motivation to bin during acquisition in terms of noise or improved quality in the end result - but there are many reasons to stay unbinned.  For cmos there is no benefit in binning during acquisition in terms of read noise - and as Tim pointed out there can be actual loss of info by trimming to 10 bits.

 

If you care about details and want to avoid artifacts as much as possible - it is probably better to process the unbinned to the final result - and at that point decide how you want to put it on the web.  There is no point in posting a 50MB image if it still looks fine at 1MB.

 

But at the same time - if you don't see any real benefit in unbinned acquisition vs. binned - even with a bit depth reduction - then it sure makes files smaller and processing faster.  And less need for more hard drives.  Which could outweigh other factors - depending on what you care about.

 

Frank


Edited by freestar8n, 10 October 2019 - 03:39 AM.


#27 AdamJ

AdamJ

    Vostok 1

  • -----
  • Posts: 101
  • Joined: 23 Mar 2018

Posted 10 October 2019 - 03:44 AM

With an ASI 1600 there is absolutely no benefit to binning.  It's not like a CCD where you get lower relative read noise and higher SNR.  With the 1600 you software binning, not hardware.  Also, the read noise is so rediculously low with that camera that even at such a great pixel scale and slow system you should have no trouble swamping enough. 

 

If I were in your shoes, I would not bin. 

Binning 2x2 will give you an increase in SNR by a factor of 2x in a CMOS as opposed to the normal ~3x for binning 2x2 in a CCD (no you dont get 4x because not all the read noise occurs in the same location within the readout electronics).  You can look at it as a case of the noise in the CMOS does not literally change you are just re-sampling, but to be honest the end effect is identical so that is just semantics. You can do the exact same thing after capture in processing to the exact same effect....but if you know your going to do that why would you not reduce your file size.

 

Adam




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






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics