Quote:
Originally Posted by Peter Ward
Binning of the IMX455 (aka QHY600M) is actually done in software, with in the case of 2x binning, the signal from 4 pixels being combined after each individual pixel has been read.
This is not the same as CCD binning which reads the combined output of four pixels as one “superpixel”. That said, there are small gains and file size reductions to be had by using 2x binning with the IMX455.
For users with long focal length systems large CCD options are still available, the SBIG Aluma CCD77-00 has 24 micron pixels and 93% QE making it one of the most sensitive cameras available, but would not be a great “pretty picture” camera due the small 512 x 512 pixel array.
I have found comparing data from my STX-16803 camera to the QHY600 when using a 3400mm focal length that the IMX455 does not fare very well on low brightness targets due its significant oversampling and low level noise structure which overcome any QE advantages. At that focal length, the KAF16803 when correctly calibrated has an ultra-smooth noise profile making it far easier to tease out hidden details.
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Just looked at the QHY website again which has been updated. It originally said there was some hardware binning on the QHY600 but now says it is software binned.
I did a test image the other night to see the visual difference between 1x1 and 2x2. 2x2 seemed to have less noise, was a bit brighter but a bit less resolution, details not quite as contrasty but it was minor. SNR was 3.76 whereas with 1x1 it was 2.8.
The 120mb 1x1 files though really slow down processing and takes 4 times as long as the 2x2 30mb files.
Greg.