Sensor sizes and f stops

Started Jan 25, 2014 | Discussions thread
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Re: Sensor sizes and f stops
In reply to Tom Axford, Jan 25, 2014

Tom Axford wrote:

I prefer to use the crop factor relative to FF. To work this out for a sensor specified as 1/2.3", you simply need to know that FF corresponds to 8/3" = 2.7" on this scale. So the crop factor for the 1/2.3" camera is 2.7 x 2.3 = 6.2.

You can use the crop factor to work out the equivalent lens (with respect to field of view, depth of field, background blur, diffraction effects) by simply dividing the focal length and the f-number by the crop factor.

So a 50mm f/11 lens on FF is equivalent to a 8.1mm f/1.8 lens on a camera with a 1/2.3" sensor (with respect to field of view, depth of field, background blur, diffraction effects).

[Of course, the exposure is still determined by the actual f-number, you do not multiply by the crop factor.]

Interesting formula, that means a smaller sensor will always produce more depth of field at a given aperture?, let´s say a 1/5,8 sensor in a camcorder at f3,4 will have more depth of field than a 1/2,3 sensor at f/5,6?? sorry if comparing digicam and camcorder is wrong but I guess the optics and system would be in some aspects be similar

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