Be careful as some M42 cameras designed to allow full-aperture metering (Spotmatic F, Pentax ES, Fujica 801, maybe some Mamiyas) can't mount some lenses properly (the 25mm Flektogon being one, at least on the Pentaxes and Fuji).
No problem with other "plain vanilla" Spotmatics and other M42 cameras.
I'll also confirm the fact that M42 adapters for Nikon need an optical element to allow infinity focus.
Rol_Lei_Nut, thanks for the clarification. I just did some reading on M42 and it is more complex than I originally thought ("M42 is M42, right?").
I am definitely skipping any adapter that contains glass. Besides, I have (almost) everything I need in my Nikkor lineup. These M42 lenses will go on a M42 body, all I have to figure out which.
Aaand... Rol_Lei_Nut, I went digging in apug archives and found your post on M42 cameras http://www.apug.org/forums/viewpost.php?p=787019 . I've learned that Rolleiflex made SLRs with different mounts, I am not sure which (or all?) camera you were talking about. I have a Rolleiflex SL35 that looks and works like new (with equally beautiful HFT 50/1.4), but never had time to use it. Would that one work as you described there (I don't mean in the last paragraph, with different finders, motor drive etc)?
The nice thing is, that with an adapter, it can use M42 lenses keeping their automatic diaphragm (it activates the pin in the lenses which have them), making it essentially a 100% M42 camera as well.
While I slightly prefer the Spotmatic (and am still looking for a mythical Spotmatic modified with a Rollei mount), in your case, I'd definitely get hold of an adapter (they're usually fairly cheap) and give your Rolleiflex a try.
Another advantage is, if you get several adapters, your M42 lenses effectively become bayonet mount lenses, albeit still with stop-down metering.
The Rolleiflex I mentioned in a recent post is the SL35-E, an electronic and AE model which was notoriously unreliable when it came out, but surviving working ones (the ones that were "good" in the first place or were properly repaired) can be nice and reliable cameras. Personally, I find it handles quite well, better than the SL35, despite my general preference for 100% mechanical cameras.
BTW: essentially the same mount and same ability to use M42 lenses via an adapter.
The one(s) I mentioned with the built-in motor and inchangeable magazines are the SL2000F, 3001 & 3003 (also essentially the same bayonet mount).
The Rolleiflex option for using M42 lenses could be quite good, also because you can pick up some Zeiss lenses which can fill some FLs where M42 lenses don't shine or where the Zeiss ones are especially nice for some reason.
While a few prototypes of the Rolleiflex 35mm SLRs had M42 mounts, the production models all had basically the same bayonet mount, but with a few tweaks over time to allow full-aperture metering and displaying the chosen diaphragm. Basically all the lenses will fit all the cameras, but will lose full-aperture metering in the "wrong" combinations.
I have a Zenit E and a Helios 44M 58mm f/2, and find it quite an excellent lens. I've never seen swirl in 35mm before I shot that lens.
For a solid feeling m42 camera, I recommend a Pentax Spotmatic.
Rol_Lei_Nut, thanks again, that was very helpful.
EASmith, Zenit E and Helios 44 always makes me feel warm inside and aggressive at the same time as it was my first kit. It was a love/hate relationship that didn't end well for the poor E. I may go to my parent's place and take a look at it again, I know it's still there.
I definitely don't remember the swirls - at the time I didn't know anybody doing LF so even if I saw them I didn't put much thought into it. Maybe it's only your copy of the lens that does it. Don't do any sudden moves around it, don't yell much and never ever grab the E by the lens, or it might stop doing the swirls. Or it might stop doing anything altogether. It's a weird thing, that Helios.
Boris, you can mount MTO 500 and 1100mm on Nikon (Or any other SLR body) with infinity focus if you simply swap original lens mount with T2 mount. MTO lens mount is identical as "outer" T2 mount. You do not have to use standard internal T2 ring with 42x0.75mm thread. I did it to my MTO 500 almost 25 years ago and also did it with MTO 1100 when I had one. It works!
Hey, I wasn't expecting to see you here :)
I sort of understand half of what you are saying there. For whatever reason, those two mirror lenses have mounts that allow them to be mounted to any SLR without much work, and that includes Nikon. Somehow I was convinced that Nikon's flange distance was at the extreme that didn't allow mounting any other lens without either losing infinity or adding glass to fix the problem; Apparently, that's correct only when standard mounts are in question. I've heard of T-mount and seen "adaptall" lenses/adapters/whatever but never paid much attention because 1) I had what I wanted available in Nikkor lineup and 2) previous sentence.
I'll definitely look into it. This M42 thing is developing into a mini-saga now. Who would have thought. Everything should be easy and simple (haha).
I'll have to grab one of my Nikons tomorrow to reload, then I'll come back to this. It's fun though, I like this M42 thing.
EDIT: Ah, I got it now. A little bit (more) of reading never hurt anybody. So F mount does not have the largest flange distance as I previously thought.