Convert in-body RF lenses to SLRs?

RioRico

I see a nearby thread here about adapters for SLR lenses to certain interchangeable-lens rangefinders. And I've seen queries on various forums about using RF lenses unnaturally. This leads me to wonder about the possibility of converting in-body lenses from wrecked rangefinders for use on SLRs. Does anyone here know of such attempts?

I understand the problems with leaf shutters, register distance, protruding rear elements, etc. Some may only be useful for closeup/macro work on APS-C bodies, or else would need m4/3 or NEX bodies. But my questions are: Can it be done? Has it been done? For which mounts? If I found a junked-beyond-repair Yashica GSN with its Yashinon 45/1.7 intact, or a Petri 7S with its 45/1.8, I would be tempted to try to fit it to my Pentax K20D, yes I would.

Maybe this has been discussed here before, but a quick scan didn't return anything. What say ye?

Sevo · Expire: 2012-12-03

Well, "possible" is just a matter of money - if you pay enough you can even have a personal unique lens developed from scratch.

If you want it within reasonable cost limits, chances are much better if you want to fit a alien lens to your Leica M - conversions to Leica are done in Japan at small workshop scale, in particular from Hexar AF and Yashica Electro.

With SLRs, you'll be limited to macro work, as pretty much no fixed lens will fit any SLR register - that limitation makes it rather unlikely that anyone already has a toolkit for such a conversion, so you'd have to pay much more than for the Leica conversions...

So far I haven't seen anyone offer conversions to an EVIL system - but that will doubtlessly change sooner or later.

cooltouch · Joined: 15 Jan 2009 Posts: 9098 Location: Houston, Texas

I second the statement about the project lens being restricted to macro work. But rather than trying to cobble together some sort of adapter to fit the lens to your camera, there is another way to proceed.

If the lens still has a front ring, this is best, but probably not essential. You'll also need another lens with a longer focal length than the one you want to play around with. The idea is to reverse-mount the project lens and attach it to the longer lens. An easy way to do this is to mount the project lens to a lens cap that fits the longer lens. That's one reason why it's best if the front ring is still there -- because after you've cut a hole in the cap, you can cement the front ring to it, and then you have a more-or-less permanent setup for macro applications. If the front ring is threaded and close to the size of the ring for the longer lens, then you might be able to find an adapter ring to fit both lenses. I've run across a few on eBay.

The shorter the focal length of the reversed lens or the longer the focal length of the one attached to the camera -- or both -- the greater the macro magnification. Calculating the actual magnification is dead simple: divide the unreversed lens's focal length by the reversed lens's focal length. So, if we have a 105mm mounted to the camera, and a 35mm reversed, we're looking at a magnification of exactly 3x. As far as focus and exposure goes, typically you would set the aperture on the reversed lens wide open and use the aperture and focusing rings of the lens attached to the camera for those chores.

calvin83 · Joined: 12 Apr 2009 Posts: 7553 Location: Hong Kong

Convert the lens from a GSN to m4/3 is possible. Check the following in a Taiwan forum.
http://www.mobile01.com/topicdetail.php?f=557&t=1505792&p=1

std · Joined: 09 Feb 2010 Posts: 1827 Location: Bulgaria

It's not very hard to do but you will need some basic tools..like a set of small screwdrivers, a stationary drill and a grinder for metal.

I have played with one 1.4/45 yashinon from Yashica Lynx 14 mounting it over a cheap c-mount-Nex adapter.

The samples re not that bad: http://forum.mflenses.com/thinking-to-convert-a-lens-from-a-fixed-fr-camera-to-nex-t34258.html

And also have one 1.9/47 hexar on parts in a bag to do for rainy days
Very Happy

RioRico · Posted: Sun Feb 13, 2011 4:26 pm Post subject:

Well, I may have done a Very Bad Thing. We have a truism that one gains good judgment from experience, and one gains experience from making bad judgments. Was this bad judgment?

I have destroyed a camera. An Ansco Autoset, the OEM version of the Minolta Hi-Matic, the same model that John Glenn took into orbit for the first handheld photos from space. I have destroyed this camera, and now it is gone, twisted scrap and dusty debris.

I have excuses, alibis. I only meant to do good. It was sick anyway; the film advance and Citizen UNI-E shutter don't work. It was cheap. I only bought it for this experiment: Can I extract the Rokkor 45/2.8 lens and put it on a usable mount? So this poor innocent camera, which otherwise could have spent its existence on a shelf next to a few other old cameras, has been sacrificed for science. Or for mere curiosity. Have I committed a sin?

The problem: Removing the lens from the body severs all control of the aperture, at least at this stage of disassembly, where I have the mounting plate, the mounting ring, and the lens-shutter unit. And the shutter still doesn't work. So, now that I have gone this far, I suppose I will need to dissect the lens-shutter assembly and remove the shutter mechanism. And I may find a way to re-engage the aperture, if I am lucky.

My advice to those with more money than time: DON'T DO THIS! BUY A LENS INSTEAD!

cooltouch · Joined: 15 Jan 2009 Posts: 9098 Location: Houston, Texas

Riorico, if you have learned anything of value from your experiences with your erstwhile camera, then I would say that it did not die a needless death. Nay, it sacrificed itself so that your knowledge would be increased manifold.

Lloydy · Expire: 2022-01-01

And for our continued entertainment and education. Wink

RioRico · Posted: Tue Mar 08, 2011 7:42 pm Post subject:

UPDATE: I have completed my dissection and partial reconstruction of the Rokkor 45/2.8 lens from the Ansco AutoSet (Minolta HiMatic) camera I so wantonly destroyed. At this point it looks pretty Franenlensish -- the bare housing riddled with screw holes, the minimal inset-hood, the M42-PK adapter glued onto the back. I still have severe problems with my picture-editing computer systems -- repair is needed -- so it will be a few days before I can post pictures.

What I have learned here: As-is, it has a fixed-focus of about 1m. The lens register is just too short for anything but close-up use on a Pentax camera. This may be a good candidate for mounting on an m4/3 or NEX body. But DON'T! The dis- and re-assembly was quite difficult and took several hours. I still must seal all the holes, to exclude dust from the camera sensor. This is NOT an experiment I would wish to repeat.