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Author Topic: 24Mpx FF vs 61,5Mpx FF: advantages of oversampling  (Read 483 times)

Guillermo Luijk

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24Mpx FF vs 61,5Mpx FF: advantages of oversampling
« on: December 28, 2018, 10:35:22 am »

Some people prefer big pixels. My conviction is that in a sensor + lens system, it's better to have more Mpx than the optics can resolve, than having more optical power than the sensor can capture.

First reason is you pay the extra sensor resolving power once, and enjoy it many times, with any lens. Second is more real information can be captured with good optics and there is less possibility of moire artifacts since close photosites act as an AA filter themselves.

The only disadvantage I can see is the higher need of resources (camera and computer CPU and memory). Even noise and dynamic range don't seem to suffer when smaller photosites are used because the lower per-pixel SNR becomes equal when considering the whole image SNR after resampling.

Test:
- 24Mpx FF camera: Sony A7 II vs
- 61,5Mpx FF camera: Olympus E-P5 (same density as a 61,5Mpx FF camera)



Same lens, scene and aperture: Canon 24mm TS-E II @ f/7,1:



200% crop on 24Mpxv FF sensor:


200% crop on 61,5Mpxv FF sensor:




Oversampling avoids moiré and captures much more real detail with optimum lens and shooting conditions. With mediocre/bad optics or shooting conditions, oversampling would simply meam no advantage but would never make things worse. I still see a chance for denser than 50Mpx sensors in the 35mm format.

PS: RAWs look dull because were developed 100% neutrally (no bright, contrast or unsharp mask). Once they are processed capture quality arises:

100% crop:


Regards
« Last Edit: December 28, 2018, 10:48:41 am by Guillermo Luijk »
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FranciscoDisilvestro

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Re: 24Mpx FF vs 61,5Mpx FF: advantages of oversampling
« Reply #1 on: December 29, 2018, 12:24:41 am »

Agreed 100%, however there are challenges such as nonlinearities and cross-talk when going to extremes.

If we start moving out of the idea of viewing images at 100%, as you increase Mpix you could even start lowering bit depth (by binning)
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