Crop Factor, Low Light and Aperture with m4/3 lenses?

Started Jun 15, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: Very simple:

Just another Canon shooter wrote:

Anders W wrote:

So you are using the DXO data to compute some "efficiency factor" that you define yourself to draw conclusions about noise, which was your starting point to begin with?

As I already pointed out, I use DxO data to compute the efficiency of the sensors to be compared. I do so on the basis of four different measures of signal-noise performance. What's wrong with that?

Do you understand how ridiculous is that?

On what specific ground would that be ridiculous?

And do you understand how ridiculous you make yourself by asking that question.

Sensorgen do very interesting analysis because they compute factors which are not in the DXO data, like well capacity and read noise in e-. Those two parameters have a clear meaning unlike your "efficiency" one.

As I already pointed out, the DxO figures on SNR on DR that I use are more direct measures of signal-noise performance, and thus image quality, than things like well capacity and read noise. That's part of the reason why I use the former.

You misinterpreted my remark about the resolution of the system. Given the same noise curve, a system with better resolution has some advantage. You can apply some NR and have a lower noise and the same resolution as a lower res system.

No I didn't misinterpret anything. The per-pixel signal-noise performance of two equally efficient sensors will not be the same if one has more pixels than the other. The performance of the sensor with more pixels will be worse on a per-pixel basis.

This disadvantage can be compensated by applying more NR (e.g., by downsampling) to the images from the sensor with more pixels. As I already pointed out, this is already done in my comparisons of sensor efficiency. The figures I use are for DxO "print mode", i.e., a resolution of 8 MP for all sensors alike, no matter how many pixels they originally have.

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