Sensor sizes and f stops

Started Jan 25, 2014 | Discussions thread
darklamp Senior Member • Posts: 3,567
No real change in noise (SNR) in final image

The cameras have exactly the same algorithms to determine the aperture so that the amount of noise is about the same,

No. This will not work.

The camera will, using the same shutter speed and ISO and using the same metering system, will use the same f-number.

If you do not do this then one shot will be darker than the other and to equalize the shots you will have to brighten it. This is essentially equivalent to raising ISO and thus increasing noise relative to signal.

So you gain nothing by using a different aperture to equalize noise ( technically SNR ) instead of using the correct aperture.

Assuming you make both sensors the same way ( !! ) and they have the same number of pixel but different sizes, then the larger sensor should have less noise.

Because of the way noise is generated in small sensors I would expect the difference to be less than e.g. doubling the size might lead you to hope. However it's very hard to make generalizations in these cases.

I would suggest that the difference between older sensors and newer ones ( small sensors ) is also less dramatic than people like to think. Large sensors have improved a lot, but there are reasons for that which do not translate so well into small sensors.

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