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Old 26-05-2021, 12:59 PM
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294MM-Pro read noise

I have a question about the 294MM-Pro and its read noise. The read noise graphs available seem to show a very similar read noise for both Bin 2x2 and Bin 1x1 modes - at least at the middle and upper end of the gain values.

My naïve understanding was that CMOS cameras did not implement the same hardware binning as CCDs, and so that 2x2 binning should double the read noise over 1x1 bin (double as the four individual read noises add in quadrature). i.e. I thought that CMOS binning in hardware was pointless (other than quicker download) and might as well be done in software. But these figures contradict that.

Is there some hardware binning being done here and there really is a hardware Bin 2x2 benefit? Also what happens just below unit gain at Bin 2 (but NOT in Bin1) to make the read noise jump significantly?

Just trying to understand if this camera is as good as the specs seem to show before I look to add it to my wishlist for approval by the financial controller in the house to replace my 1600MM
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Old 27-05-2021, 11:38 AM
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The 294 has a 4 subpixel structure which is unique. Hence the genuine 2x2 binning and its benefits.

Other CMOS don't do hardware binning except for the QHY600 and perhaps the 268.

Banding at 47mp ca be the real issue with the 294.

Greg.
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Old 28-05-2021, 05:33 PM
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DiscoDuck (Paul)
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Thanks Greg.
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