Re: Basic newbie question on cmos sensor and optics


"KLFrosty" <Keith.L.Frost@xxxxxxxxx> ha scritto nel messaggio
news:1115251774.065197.144440@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

>>
>> It's counter-intuitive to me why a much bigger, more costly sensor,
> with
>> similar pixel size, given the same target image and illumination,
> would give
>> me back a more noisy image...
>>
>
> It depends on the two different custom designed optics you mention.
> The bigger, more costly sensor, with more pixels of a similar size,
> needs MORE LIGHT to illuminate those pixels, so your optics must be
> designed with a larger field of view, in order to provide that light.
> If you take the same optics, and just increase the magnification, so
> that the real field of view is the same, but your resolution just went
> up -- your effective sensitivity will go down in proportion as the
> sensor area goes up, just as you are worried about. So, if you really
> need that sensitivity, either use the higher resolution sensor to
> image a larger (real) field of view, or use a bigger lens to collect
> more light at the higher magnification, so that you can view the same
> real field of view, with the same sensitivity, at higher resolution,
> with (incidentally) reduced depth of field (inversely proportional
> to your lens diameter).
>

Thanks a lot for your answer.

It helps, just reading some books left me with more doubts than before :-)









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