On February 27, 2003 07:34 am, John Mustarde wrote:
> On Thu, 27 Feb 2003 00:21:28 -0600, you wrote:
> >So, yes, the 50mm lens on an APS sized sensor would have the same angle of
> >view, d.o.f. at same aperture, perspective, and "flattening" effect as a
> >piece of 35mm film cropped. But so would a 75mm lens on a full-sized piece
> >of 35mm film.
> >
> >Hope this is clear. This is one of those perennial questions in
> >photography--it just always comes up again and again and again.
> >
> >--Mike
>
> I support Mike's observation. The DSLR's smaller sensor acts like a
> 1.5x teleconverter. Your lenses just get longer with the smaller
> sensor, no matter what.
>
The way it makes the most sense to me is to think in terms of the film
moving. You've got a cone coming out of the back. The further back the film
plane the wider the lens.
x
x x
x x
x x
x x
x x
x x
Your piece of film needs to fiit inside that cone. So if you only change the
film size the same lens can go from very long to wide.
Nick
