Quote:
Originally Posted by RickS
The second thing is that you're measuring more photons in a single pixel when binned.
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Maybe that's true for CCD, but that's not what I'm finding with my CMOS. For me, the mean value stays the same - it's the StdDev that changes - which I guess means there is less noise and so the signal can be boosted to the same effect as having captured more photons?
Quote:
Originally Posted by RickS
I like noise reduction better than binning because you can specifically target the areas where noise is most visible: the low signal areas and small spatial scales.
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That actually makes a *lot of sense.
Quote:
Originally Posted by RickS
Summary: IMO, binning is usually a waste of time  The only justification I can find for it is when you're chasing dim NB targets and can't do subs that are long enough to be sky limited. |
I think that's my issue - how do I use binning to save time on the field? This necessitates less integration time per sub and therefore shorter (or less) exposures. Since binning during capture (I hesitate to call it 'hardware binning') doesn't actually increase the mean values of the sub, do I;
1) Halve the exposure, but still shoot at 1x1, then bin in post? Surely some of the binning gains are lost to increased read noise contributions?
2) Halve the exposure and shoot 2x2. The median values will be the same as (1), but there will be less SNR which will allow me to boost the signal 2x to arrive at a binned sub of the same median values as (1).
3) Halve the exposure, live with the noise and use selective masking and noise reduction in post instead of binning.
There's also the difference between integer resample and Pixelmath combinations. If you choose average as the method in Integer Resample, you won't get out of range values, you just reduce the noise (so I'm told, but in my experiments, it seems to have very little effect on noise). Which is different from straight binning 2x2 in PixelMath, which *does reduce noise with the danger of out of range values (clipping), using;
Code:
x2 = 2*x();
y2 = 2*y();
pixel( $T, x2, y2 ) + pixel( $T, x2+1, y2 ) + pixel( $T, x2, y2+1 ) + pixel( $T, x2+1, y2+1 )
Best,
Markus