Pentax *ist - usability of older lenses

My son has a Pentax film SLR and is interested in progressing to DSLR.

Has anyone actually used film lenses on an *ist body? He has the normal 50mm
and a zoom to about 80mm as well as a beast which covers 70 to 400mm. Are
these lenses usable without distortion or black edges etc?

Thanks.

Gerrit

In article <42f76701$0$16506$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
"Gerrit 't Hart" <gthart RemoveThis @sad.au> wrote:

> My son has a Pentax film SLR and is interested in progressing to DSLR.
>
> Has anyone actually used film lenses on an *ist body? He has the normal 50mm
> and a zoom to about 80mm as well as a beast which covers 70 to 400mm. Are
> these lenses usable without distortion or black edges etc?

Gerrit-

Yes.

I have the *ist DS. It came with a kit lens that isn't bad, and has a
wider angle than any of my other lenses (18mm). I think the kit lens is
worth the difference between the kit and the body alone.

One thing to consider, regardless of lens: the *ist sensor is smaller
than a 35mm film frame, so pictures are cropped compared to using the same
lens on a film camera. The result is as if the lens has 1.5 times the
focal length.

If his film camera is autofocus, the autofocus lenses will work perfectly
on either body.

If the lenses aren't AF, but are the KA lenses, they will work (in KA
mode) the same as AF lenses on the *ist, except for being manualy focused.

If the lenses are the older non-A K mount lenses or KA lenses in
aperture-preferred mode, they work but only in full manual mode.

I recently obtained a screw mount-to-K mount adapter but haven't tried
it. I understand it allows use of old screw mount lenses on the *ist in
full manual mode.

The camera's autofocus system can be used for focus-assist with manually
focused lenses. Even so, I find it difficult to manually focus the camera
since there is no split-image focusing aid in the viewfinder.

Fred