Schneider M42 lenses not reaching infinity

[connloyalist]

I have a curious problem and wonder if anyone else has seen this.

At the moment I own 18 usable M42 mount lenses. Those 18 lenses include 3 Schneider's and 1 Isco (I am not counting a second Isco which has all kinds of problems). I own three different M42 to M4/3 adapters but the one I always use is a Novoflex. Camera is an Olympus E-M1 Mk.III

Both of my Schneider 135mm lenses don't reach infinity, the focusing ring ends just a little short of where it should be to get infinity sharp. These two 135's are different styles by the way, not two copies of the same lens. One is a zebra the other one is the "black with brown trim" styling. My Isco 35mm 2.8 (zebra with window, a Schneider Curtagon, apparently) does reach infinity but with absolutely no margin of error. Interestingly, my Schneider 50mm 1.9 Xenon is fine. Comfortably reaches infinity with just a little room to spare, as it should be in my opinion.

None of my 15 other M42 lenses (Takumar, Carl Zeiss Jena, Meyer, Hanimex branded Tokina, Steinheil) have this problem. All these are just fine in this respect.

Did Schneider / Isco work by a different M42 specification? A bit too enthusiastic in getting things perfect?

I am interested in hearing your thoughts.

EDIT:
Quick test on the GX-7 with the Novoflex adapter: same thing.
Fuji X-T1 with K&F Pro adapter: it reaches infinity but only just, no margin for temperature differences etc.
E-M1 MkIII with K&F "standard" adapter: this one reaches infinity well before the end of the focusing ring
E-M1 MkIII with K&F Pro adapter: this one reaches infinity well before the end of the focusing ring

On all three of the K&F adapters, that is on M4/3 and Fuji XT, the K&F adapters have the lens with the aperture not at the top but at the one o'clock position. On the Novoflex, the lens is where it should be.

Unfortunately I don't own a Novoflex M42 to Fuji adapter.

So the bottom line is, I can use the K&F standard adapter on the camera I usually use (the E-M1 MkIII) for these lenses.

Regards, C

[Doc Sharptail]

I would try on a known good condition M-42 film body before blaming the lenses.

The only infinity problems I've had in my adapter-less experience have all occurred on zooms- some of them OEM.

-D.S.

[connloyalist]

[calvin83]

This is not uncommon for adapters with thickness close to ideal. My Rayqual adapter will not allow my Mir-24H to reach infinity. I have to use a Kipon adapter for this lens.

[Doc Sharptail]

[jamaeolus]

I have had this issue with quite a few lenses. I purchased a close m42 ring (I have a Sony a7riv) and various short helicoid m42 -m42 adapters. You can get extension tubes in mm increments from 4mm up. This almost always works but its fussy and tedious.Another option is trying to adjust infinity on the lens. I have done this with Contax lenses but not with schneider. I'm not sure it's possible. A third option is modification of the Novoflex adapter. Most adapters have final flanges mounted to the moving bits with typically 4 small screws. Removing the front or back flange and carefully lapping a few tenths of a mm off using a very flat surface and a sheet of 100 grit sandpiper has worked for me. Be careful to rotate the flange every few strokes to guarantee that the flange stays true.

[visualopsins]

Can't reach infinity == 1) adapter too thick, or, 2) the Schneider lenses are not completely seating onto the adapter(s), or 3) the infinity has been adjusted. Given your test results, I vote #2.

[connloyalist]

[connloyalist]

[alex_d]

Option #4:
- you have too many lenses, which is keeping you from taking more photos

[connloyalist]

[kiddo]

best choice is to adjust lens to one adapter and stick with it , don´t mix them

[Alun Thomas]

I have lenses where the M42 thread is longer than average, they won't seat on an M42 adapter with the internal ring design to actuate the aperture pin. So I have a second adapter for those lenses and have altered the internal ring so that it doesn't interfere with the lens, it just acts as the spacer to keep the flange distance at the distance designed for the adapter.

[kypfer]

Just a suggestion :-
A Pentax K-mount DSLR will have the same registration distance as the M42-mount cameras that preceded them.
Pentax have supplied an M42-K mount adaptor of effectively zero thickness (it fits inside the K mount) since they introduced the K-mount in 1975.
A cheaply available 6Mpixel Pentax DSLR, with this adaptor fitted, can make a perfectly good M42 lens test bed, even if you use it for nothing else.
Of course, if you just want optical confirmation in the viewfinder that the lens is working, any of the multitudinous K-mount bodies (with an appropriate adaptor fitted), or M42-mount bodies, will serve to provide this function, even if they don't work otherwise.
Do note, the Pentax-made adaptor is an accurately-made device that doesn't need any special tools to fit or remove it, just a finger-nail or the tip of a ball-point pen to release the spring latch.
However, the third-party "replica" adaptors are usually supplied with an extraction tool, to overcome the machining inaccuracies of manufacture, and these adaptors can be a source of frustration when they jam in the camera!

My experience with older M42 lenses (of which I have many!) is that any one that wouldn't focus accurately had either been forced (evidence of "skid-marks" where screws have slipped around, having disassembled the lens), or that it had been disassembled and reassembled incorrectly ... again, often evidenced by chewed-up screw heads and associated scratch marks caused by unskilled hands and/or inappropriate tools.

Further to all that, my limited experience with lens adaptors for mirrorless cameras has shown that the accuracy of manufacture can vary significantly

[connloyalist]

[connloyalist]

OK, I found my Pentax ME-F and using info from the Pentax forum was able to unstick the mirror and advance lever by smacking the bottom of the camera in the palm of my hand. Not something I would contemplate doing with any modern camera. I installed the original Pentax K to M42 adapter I have and then tried one of my Schneider 135mm M42 lenses.

It does reach infinity, but with absolutely no room to spare. Also, the lens ends up with the aperture mark not top center but at about one o' clock. Assuming the camera set up now counts as a correct M42 film camera I cannot imagine that Schneider would sell a lens that is not rotated correctly. Conclusion, this lens has probably been disassembled at some point.

Regards, C.

[BrianSVP]

IIRC, the lenses made for the Wirgin Edixa system,which included Iscos and Schneiders, have a slightly (like .04mm) difference in FFD from regular m42 and have their 12 o'clock position at a slightly different point, which probably explains both of your issues. I believe this was to accommodate the shutter release/stop down armature, similar to those used on Alpas and Exaktas, that was used on some lenses for the Edixa Reflex.

One thing about the Pentax OEM m42 adapter, as well: when mounted on a camera, it is not supposed to sit perfectly flush with the K bayonet, but rather fit loosely somewhat inset. Screwing in the lens causes its base to press against the K bayonet, pulling the adapter forward. When used in conjunction with another adapter on digital, or when using a lens whose base is too narrow to press against the exterior bayonet, it doesn't always do this, which can lead to infinity problems.

[connloyalist]

[connloyalist]

More on the topic of Edixa lenses:
https://forum.mflenses.com/the-edixa-m42-mystery-t51861.html


Regards, C.