Pentax *ist - usability of older lenses

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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

 

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

 

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Archived from groups: rec.photo.digital (More info?)

"Gerrit 't Hart" <gthart@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?

Distortion and vignetting (which is what I assume you mean by "black
edges") are going to be *reduced*, if anything, when using film lenses
on a DSLR. I have the ist-D and frequently use older manual focus Pentax
lenses with it.

"F" and "FA" series lenses will work in all exposure/metering modes and
will obviously autofocus.

"A" series lenses (1982 and later) will work in manual focus mode and
all metering modes.

"M" and "K" lenses will work in manual focus mode and require a kind of
"automatic stop-down" metering with the camera set to manual metering:
On the ist-D you press the green button on the top of the camera, which
then stops the diaphragm down to shooting aperture and sets the shutter
speed appropriately. On the ist-DS this is achieved by pressing the AE
Lock button. Very quick and easy. I use my 15mm f/3.5 frequently this
way.

In short, you should have no issues with lens compatibility.


--
Mark Roberts
Photography and writing
www.robertstech.com

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

Gerrit 't Hart 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?

I recently bought a Penatx *ist-DS and I'm very sastisfied with it.
My line up of lenses include a Sigma 17-50mm (kit), Tamron Adaptall-2
28-200mm, Mir 1b 37mm and a Peleng 8mm.
All of the lenses seem to work fine.
The Mir and Peleng lenses are used with an M42 to K adapter.
The only thing to realy watch out for is with manual K-mount lenses,
that is the focus switch is set to MF, otherwise the viewfinder LEDs
just flash and the shutter won't trip.
I realy like using the 8mm fisheye now, with the ist-DS because now it
is a full frame lens