[Elphel-support] Elphel 353 - Question about Focus

[support-list]

Hello David,

Do you use decimation or just a smaller window to reduce the frame size to 1280x720?
Decimation on all Bayer mosaic sensors is not optimal, it is designed mostly for a quick-preview or viewfinder mode. Aptina datasheet has a full explanation, but in short, it is not possible to throw away each other pixel - instead of RGRGRGRG line you will get RG--RG--, so there will be two-pixel gaps, not one pixel ones as in the case of a pure monochrome sensor. Binning will produce the similar results

So I would recommend using window, not decimation/binning, and if you anyway use only 1280x720 you may get better results with a 1/3" or even a 1/4" lens. The full frame will have dark image outside of the center area, but it may be easier to get higher resolution in the center you need. Also fixed-focal length lenses generally produce better image than varifocal ones, so you may use the current lens to find the optimal focal length and then put a fixed-focus one instead. There are many lenses 1/3" and 1/4" format we can try, including M12 ones with adapter.

Andrey





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