[Nesster]

In my bottom feeds, I've accumulated a few M42 mount lenses. Most of them are fully interchangeable, compatible with my Spotmatic SP1000, Fuji ST605, both Pentax and Bower M42->K adaptors, the Vivitar extension tubes, and the Pentax bellows.

But there are exceptions:
The Fuji 55/2 that came with the ST605 isn't happy with the Spottie or the adaptors, there are bits sticking out the back.
The S-M-C Tak 28/3.5 will NOT mount on the Spottie, and the Pentax adaptor. It mounts in the Bower and the tubes and bellows however. I think there's a thread out of whack on it.
The Auto Rikenon 28/2.8 that just arrived came with a thin plastic shim on the mount. I wondered about that. Without it, on the Spottie, it screws PAST 12 noon and settles 45 degrees beyond. With it, it stops at 12 noon, but will NOT get infinity. Haven't tried this with the ST605 as yet.

It's funny but it may turn out that the Fuji is the most compatible of my cameras.

[ryan s]

The Fuji's aperture communication pin sticks out of the lens, and the ring on the camera is on the outside (instead of inside like the Pentax K). It's a pain to unscrew the lens to change the aperture...

Check the back of the Tak. There's a small pin which may be stuck, not allowing the lens to thread on. Here is a pic...notice the red dot is where the pin ends up, but you can see what would happen if the pin was stuck. Working the A->M switch should solve it.


As for the Ricoh...the only thing I can think of is that the camera's mount is 1/4 rotated... Just throwing out ideas...

Oh: The Fuji lenses aren't technically M42. They're known as "Fujica ST" because of that pin

[Nesster]

Thanks for the thoughts - Ryan's picture is of the s-m-c part way screwed into the K adaptor. You can see in the cut out part of the adptor, there's a tiny pin on the screw mount. This locks the lens A/M switch.

My switch unfortunately works. The far end of the threading of the screw seems to be knocked upwards - there's bright metal on the top surface of the thread, as though the Pentax threads had tried to force the lens thread, when I applied pressure to the mounting process.


I'm still scratching my head about that Ricoh, the lens looks all lined up: the aperture etc set is opposite the aperture pin. If I rotate the mount 45 degrees, then the aperture pin wouldn't line up. The infinity stop on the focus lines up right as well. I do see set screws on the different lens rings, perhaps the whole thing was re-assembled 45 degrees off. I won't do anything drastic until I've figured this out.

[ryan s]

Eww...never want to see bright metal on threads. Isn't T-mount also 42mm, but with a different pitch? Then again, you would see that it's got extra metal on the end of the lens...

That Ricoh is weird...I asked about the camera mount because I accidentally put it on my TLS roatated, so the lens didn't sit right. But the infinity focus...I just don't know. Ricoh only made (to the best of my knowledge) Pentax mount lenses, with the added pin of the R. Even if it could have been a Minolta, changing the mount to M42 would cure the infinity issue

[Peter Zack]

Yes T mount is also 42mm with a different pitch. And it's close enough you could force it on for a turn or 2 and think it just cross threaded when actually it's binding because it wasn't meant to mount to an M42 camera but to a T2 adapter.

[Nesster]

On the S-M-C Tak, I think the final turn of the screw thread has been pushed up, or it got out of the factory out of spec. I'd love to try it on a SPF or ES however. Thing is, I don't actually need the lens as my Super copy is actually slightly better, at least when there's no lighting issues.

The Richoh has three screws holding the mount - so I could turn it by 1/3... but then, will the aperture pin match the innards (I don't think so) and infinity, focus/aperture mark, and the A/M switch all line up with the pin perfectly now. The lens itself is obviously in a more used condition than its sibling the 135 is (the latter is near-perfect) so perhaps someone took it apart and put it back together wrong. For $10 invested I wouldn't spend too much time or money on it, unless of course it turns out to be a super lens, better than my other 4.