1" sensor versus APS-C

Started Aug 15, 2013 | Discussions thread
nigelht
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Re: 1" sensor versus APS-C
In reply to nigelht, Aug 22, 2013

nigelht wrote:

This is the end of the road for me. I have said all there is to be said. What it comes down to is that you either do not understand or do not accept when I tell you, and referred you to the exposure vs brightness article, that exposure is all about how much light the sensor receives. when two sensors receive the same amount of overall light, provided they are of the same efficiency, they will generate more or less the same image, even if it means light is more concentrated on the smaller sensor. ISO on the other hand is a standard for output brightness, it is not part of exposure itself. Until you get that through your head you not be unstuck.

Good luck.

The fact is that you are wrong because you assume that you can always make up 3 stops of sensitivity on your FX sensor vs the CX sensor. That's not true even with the v2 vs D600 without post processing. If the v3 gets a backlit sensor and gains a stop or two sensitivity that won't even be true against the "same gen" 2013 D4.

Any gain you apply can be equally applied to both sensors and there isn't always 9 dB difference in their native sensitivity. This native sensitivity difference matters most not when both sensors have strong signals to work with (plenty of light) but when the signal is weak (very little light).

The other thing that was bugging me was your assertion the pixel size doesn't matter. It does given it determines the number of photons that hits each sensel.

For the D600 vs the V2 the sensel are 5.9x5.9 vs 2.86x2.86 and the areas are 34.81µ vs 8.17µ. A factor of 4 difference.

So if the D600 sensel gets 1000 photons the V2 only gets 250 photons hitting it. But in your example with a 3 stop difference the D600 sensel only gets 125 photons. Purely as a function of area.

Even as a function of total sensor size a FX sensor area is only 7.4 times as large as the CX sensor.

So with the same 1000 photons on the entire FX sensor then 135 hits the CX sensor.  Again drop 3 stops and the FX sensor ends up with 125 photons physically hitting the FX sensor vs 135 hitting the CX.

So thanks, this was fun, I learned a lot (not from you but from reading primary material) and you're wrong about equivalency between a CX and equivalent FX lens and the original poster correct except for leaving off DoF.

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