Re: pinhole photography/ calculating focal length
11 Jul 1997 23:42:32 GMT
Colyn Goodson <firstname.lastname@example.org> writes: > Bozhidar Dimitrov wrote:
> > Adam (email@example.com) wrote:
> > : >"Geoffrey V. Brown" <firstname.lastname@example.org> writes: > Well, I've got some extra film and want to mess around with some stuff
> > : >> this weekend.
> > : >> I'm thinking about trying some pinhole photos, but doing them with my
> > : >> canon T-90 with the lens removed and a plate in its place. I'm
> > : >> wondering how if anyone has any suggestions on how to calculate the
> > : >> focal length.
> > : >I do this often with a Pentax Spotmatic with a body cap with a pinhole in it.
> > : >It is about equal to a 45mm lens, and I would guess that it will be about
> > : >the same on a T-90.
> > It will depend on the camera register (distance between lens mount and
> > film).
> > Boz Dimitrov
> >>The only way to change focal length is to move the pinhole closer to or farther away from the film plane......
You a right that it will vary somewhat, but it is going to be around 45mm. It might be 40, it might
be 50; I doubt if the original poster needs to know that exactly.