Adapter for Pentax K mount to screwmount body?

winger · Dec 9, 2014

I haven't any mention of the existence of such a thing, but would LOVE to use some of my more recent lenses on my old H1a. I also know this was one thing my dad really wanted back in the day. Is there any way to do it DIY-style?

frank · Dec 9, 2014

Not possible based on what I know. It's like the ltm to M adaptor, only works for screw mount lens to bayonet style body, not the other way round.

E. von Hoegh · Dec 9, 2014

winger said:
I haven't any mention of the existence of such a thing, but would LOVE to use some of my more recent lenses on my old H1a. I also know this was one thing my dad really wanted back in the day. Is there any way to do it DIY-style?

Machine a K-mount flange to put on the H1a body in place of the 42mm screwmount - I measured this out and IIRC it's possible but rather impractical.
There's a screwmount lens to K-mount body adapter, Pentax though of this while designing the K mount. But, the diameters are wrong to go the other way.

adelorenzo · Dec 9, 2014

Pentax K mount and M42 mount have the exact same flange focal distance. So you'd have figure out an adapter that kept the lens in the exact same spot.

frank · Dec 9, 2014

adelorenzo said:
Pentax K mount and M42 mount have the exact same flange focal distance. So you'd have figure out an adapter that kept the lens in the exact same spot.

This is why my 50f1.4 Takumar screw mount lens won't focus to infinity on a k mount body.
I guess Leica was smart to add a millimeter or 2 to this distance on their M mount bodies. Their screw mount lenses do focus to infinity with the ltm to m mount adaptor.

Oren Grad · Dec 9, 2014

frank said:
This is why my 50f1.4 Takumar screw mount lens won't focus to infinity on a k mount body.

Something is wrong with your equipment. A properly-made M42-to-K adapter on a K body in proper adjustment should allow focus to infinity. The adapter is intended to sit within the bayonet mount and not add anything to the flange-to-film distance.

frank · Dec 9, 2014

Oren Grad said:
Something is wrong with your equipment. A properly-made M42-to-K adapter on a K body in proper adjustment should allow focus to infinity. The adapter is intended to sit within the bayonet mount and not add anything to the flange-to-film distance.

My adaptor definitely has a lip that adds to the flange to film plane distance. It's not a Pentax brand, just a cheap ebay purchase.

Oren Grad · Dec 9, 2014

frank said:
My adaptor definitely has a lip that adds to the flange to film plane distance. It's not a Pentax brand, just a cheap ebay purchase.

My Pentax-branded one has no lip and sits perfectly flush with the K body mount.

frank · Dec 9, 2014

My adaptor bad.

Prof_Pixel · Dec 9, 2014

Oren Grad said:
My Pentax-branded one has no lip and sits perfectly flush with the K body mount.

Yup.

Fixcinater · Dec 9, 2014

frank said:
My adaptor bad.

Yep.

You can get knock-off adaptors without the flange, same cheap price.

Sent from my iPad using Tapatalk

winger · Dec 10, 2014

APUGuser19 said:
I wonder if its possible to junk out an old K mount body for its lens mount flange ring thingy, and affix it to a screw body.

There would still be some diameter differences and flange to film plane distance to deal with, but maybe I just don't need infinity focus anyway.

Thanks all! I didn't think the real thing was out there, but maybe I have some ideas.
I put a Lensbaby Composer on my Christmas list (no idea if I'll get it) and I just thought it would be easier to use on that body instead of on the PZ1p. Not that it'll be tough to use on the PZ1p, but the H1a is very comfortable in my hands and is totally manual.

ciniframe · Dec 10, 2014

If a person wanted to try and put a K mount on an old H1a body they could get one off of a Vivitar or other third party 2X extender. They usually go cheap, not much demand. However it would no doubt require some very precision machining of the body so much work if possible at all. And even then is there any way to stop down the lens to working aperture before exposure?

Yeah, just look for some M42 lenses.

jochen · Dec 10, 2014

Hello,
one advice from my side: Not all later Super Takumar or Super Multi Coated Takumar lenses can be used on older Pentax bodies before the Spotmatic. Especially the first type of the 1.4/50 mm with 8 lenses and the first 1.4/50 mm with 7 lenses can make trouble as the rear lens protudes so far that the mirror would bump against it and the lens and the mirror mechanism could get damaged. The pin for closing the automatic diaphragm can make trouble on some older models as the actuator plate of the body had another form and the pin of older Auto Takumars was located at a somewhat different place.
Please check this in the literature before damaging lens or body. More "m,odern" bodies like SP (50th anniversary this year!!), SP II or SP F are plenty on the market for acceptable prices.

lxdude · Dec 10, 2014

Fixcinater said:
Yep.

You can get knock-off adaptors without the flange, same cheap price.

I got one of those, and it jammed so badly that I had to cut it to remove it. Only the genuine Pentax adapters from now on for me!

Xmas · Dec 10, 2014

@Winger

You could try a K1000 without a battery?

elekm · Dec 10, 2014

I once bought a cheap 42mm to K mount adapter, and it wouldn't focus to infinity.

I found a Pentax-branded adapter, which ended up being the same price as the bargain adapter. Focused to infinity.

For some things, it's worth it to spend the extra money and get the quality that you expect.

Bottom feeding has its limits.

winger · Dec 10, 2014

Xmas said:
@Winger

You could try a K1000 without a battery?

I might. They're pretty cheap these days. And there's no way I'd do anything permanent to my H1a - it's technically still my dad's (according to mom).

Xmas · Dec 11, 2014

winger said:
I might. They're pretty cheap these days. And there's no way I'd do anything permanent to my H1a - it's technically still my dad's (according to mom).

the kit lens for the early Pentax will have a nice signature Id a be putting the lens on the adapter and using it on a K1000...

lxdude · Dec 11, 2014

winger said:
I might. They're pretty cheap these days.

I suggest you spend the same money or less and get a different K-body. The K1000's are overpriced for what they are, apparently due to their wide use as a starter camera. I know that at the local colleges, the instructors give the same advice they've given for decades- to get a K1000. Newer K1000's were not made in Japan, and seem to have been somewhat cheapened in materials.

A KM is the same as a K1000, but has both DoF preview and a self-timer. The KX has DoF preview, self-timer, and aperture value visible in the viewfinder.
To compare prices, a K1000 in BGN condition is presently available at KEH for $133. They have a chrome KX in BGN for $84.

lxdude · Dec 11, 2014

I also suggest you look into getting some screw-mount glass for your H1a. I have a lot of SMC-M and SMC-A lenses, and they are very nice, but there's something about those Takumars.

E. von Hoegh · Dec 11, 2014

lxdude said:
I also suggest you look into getting some screw-mount glass for your H1a. I have a lot of SMC-M and SMC-A lenses, and they are very nice, but there's something about those Takumars.

I have a 55/2.2 Auto Takumar, I think it was the kit lens on the H1 or the H3 - it's the one with the slider on the mount to set the auto diaphragm.
It's a very nice lens, and the price was right - it came out of a box of junk at the local 'transfer station' AKA dump.

winger · Dec 11, 2014

My dad filled out a decent selection of lenses when he was still using it. I have:
Auto-Takumar 35mm f3.5
Super Takumar 55mm f2
Super Takumar 135mm f3.5
Also a 2X teleconverter and a 300mm

I don't know that any of these are holy grail - type lenses, but they've always done well by me.
lxdude - Thanks! I'll keep my eyes open for a KM or such.

lxdude · Dec 11, 2014

Bethe- I suggest you get the Super-Takumar 200mm f4 to go with the others. I have had one for decades and would never get rid of it. If you wanted something wider too, I recommend the 28mm f3.5.

winger · Dec 11, 2014

lxdude said:
Bethe- I suggest you get the Super-Takumar 200mm f4 to go with the others. I have had one for decades and would never get rid of it. If you wanted something wider too, I recommend the 28mm f3.5.

Thanks! I might look for those. The ones I use the most are the 35mm and 55mm.

Adapter for Pentax K mount to screwmount body?

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