In article <32c6fe72.2750429@news.microweb.com>, chi@microweb.com says...

>When comparing APS to 35mm (or other different size films), I know the
>focal length is effectively increased for APS when using the same
>lens. But, what does this do to the f-stop? Increase? Decrease?
>Remains the same? It just seems that if you shine the same amount of
>light on a smaller area (I don't know if that is true), wouldn't you
>get more light intensity.

Using the same lens (designed for a larger format) on APS does nothing
to the coverage - the smaller format just crops out a smaller area of
the unchanged lens coverage. Coverage has nothing to do with f-stop,
which is the FL divided by the diameter of the aperture hole (a 100mm
lens with a 25mm diameter aperture is f4, whether it covers 16mm movie
film, or 4x5 sheet film).
Hope This Helps