[Quicksand]

This thread rings a few bells for me!

I have a Peleng 17mm fisheye (strange beast, rarely encountered) that also comes with an M42 mount. It sounds just like yours -- the "T-like" mount has three grub screws that hold it on to a flared but otherwise smooth barrel.

It worked fine this way, and still does. (It does need the clear rear-mount filter to be attached for it to focus, though -- removing the filter throws off the focus.)

I got the bright idea a year or so ago to try to retrofit a T-to-K-mount onto it, so I wouldn't have to mess with the M42 adapter. It attached OK (as described basically in the thread troyz links to), but I never got that combination to focus correctly. It held the lens too far out from the camera body.

So I went back to the original M42 end piece. I suspect that's some odd custom piece and can't be easily replaced.

I can't help you with the exposure shift problem. That stumps me.

[Ira]

Information about modifying a standard T2 mount for use with the Peleng 8mm (FYI I haven't tried this):

Mod T mount.jpg photo - Pete Ganzel photos at pbase.com

Manual Focus Forum / Russian interchangeable mount lenses (T/A)

I'm not all that technical, so can you or anyone clarify something from me?

I don't know WHAT the heck they're talking about in the thread, but according to the photo in the second link, all he did was shave the front edge of the rim 1mm, correct? And possibly modify the screw holes due to the shaving?

I happen to work where we have machining equipment (I don't know what any of it does--I just stare at it), and people who actually know how to use it. So maybe I'll have someone shave it in 1mm increments until it works.

In addition, it would seem that screwing the 42-pk adapter to the lens (with real screws), ignoring the M42 thread aspect of it, would work too--allowing use of the lens with the body's native mount. If focus isn't right, you could easily shim between the lens and mount to make it right.

[Ira]

This thread rings a few bells for me!

I have a Peleng 17mm fisheye (strange beast, rarely encountered) that also comes with an M42 mount. It sounds just like yours -- the "T-like" mount has three grub screws that hold it on to a flared but otherwise smooth barrel.

It worked fine this way, and still does. (It does need the clear rear-mount filter to be attached for it to focus, though -- removing the filter throws off the focus.)

I guess the 8mm is just different dimensionally than the 17mm.

Also, I was pretty sure that the rear filter was removable and necessary, but that entire assembly is the actual filter, correct? What I highlighted in red? Both the glass and the plastic are one piece?

[Quicksand]

I guess the 8mm is just different dimensionally than the 17mm.

Also, I was pretty sure that the rear filter was removable and necessary, but that entire assembly is the actual filter, correct? What I highlighted in red? Both the glass and the plastic are one piece?

I'm not sure about that. On my 17mm, the rear filter is just a small glass disc with a metal rim around it. Like a regular front filter, only much smaller. It's not nearly as big as what you highlighted in red.

[Ira]

Well, me and my engineer see that the only way to make this work properly and like a rock is to epoxy it--just the M42-PK adaper directly to the lens.

She's dry, but I'll wait until I get home to try to mount and check focus.