Posted by Rick Merrill on 09/07/06 16:06

Richard Crowley wrote:

> Acurajustin1978 wrote ...
>
>>I know what a CCD is... but when I see the sizes listed it will say
>>something like 1/6 or 1/7.5.
>>What does this mean? One sixth of an inch?
>>Obviously I'm guessing bigger is better.
>
>
> It is the *diagonal* measurement of the imaging surface,
> measured in inches (for better or for worse). It is measured
> diagonally because lenses are round and that is the *diameter*
> of the image that must be delivered by the lens.
>
> Bigger means more sensitive imaging devices (because
> there are more photons hitting each "pixel" to turn into
> an electrical signal). However, bigger also means larger
> (and significantly more expensive) lenses to deliver an
> appropriate image to the chip.
>
>

Mmmm, I think you are on to something: the round lense image must
fit INSIDE the square CCD; therefore it would make more sense for
the CCD to be measured along it's edge: the diameter of the round image
that would just fit.

So I think CCD is measured square, not diagonal like the big screens.

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