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M42-to-PK adapter with inner flange for auto-pin lens
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PostPosted: Wed Jul 01, 2009 10:20 pm    Post subject: Reply with quote
Thanks for the feedback everyone...


PostPosted: Thu Jul 02, 2009 11:03 am    Post subject: Re: M42-to-PK adapter with inner flange for auto-pin lens Reply with quote
hk300 wrote:

I have tested this adapter with many lenses, and most lenses (including my Carl Zeiss Jena 20/2.8, 35/2.4, 50/1.8, 135/3.5, Pentacon 50/1.8, 135/2.8, Tak 50/1.4, ...) will be able to go from full open to f22 or even smaller aperture.
However, some lenses can only go up to f11 and one only went to f8. Note sure if those lenses were having a faulty/sticky aperture auto-pin.


I think its not a problem with the blades. I have found that if I depress the pin too much, the aperture does not operate properly. The range of operation of the pin seems not to be from fully extended to fully depressed.
I found that if I depress the pin with my finger there is a point where resistance is different, so I can detect that point and glue the pin there.

As this point may vary with lens, I don't see a way to working it out on these adapters.

I do like the idea though. For the lenses that do work, I wouldn'y mind converting them to PK. As anyone done this?


PostPosted: Sun Jul 05, 2009 8:48 am    Post subject: Reply with quote
It is possible I did it with the Telear 200/3.5 that I got from Sichko, its not an auto lens but the same should apply. This is normally a Nikon fit lens but comes with an complete end to change it to M42. So firstly I changed the ends over, its only 4 small screws to do it, then put on a Roxsen infinity m42 -pk adapter, one of Alex's should work just as well. Then take off the screw that holds on the spring clip and remove the spring clip. Put the screw back in and use it to tighten the adapter to the m42 thread, but not too much or it will deform the thread. AS there is no clip now the lens will go on and off ok but can't lock, there are 2 solutions to this, 1) drill a hole in the bottom of the lens so that the PK mount locking pin will catch it, as in a PK mount lens or as I did, 2) instead of a larger hole, drill a small hole and use a small self tapping screw as a lug for the pk mount to catch. I find this is better but it will only work on some lenses that have enough clearance to do it. So I have a pk fit Telear 200 and the modification is removable. Very Happy


PostPosted: Sun Jul 05, 2009 12:09 pm    Post subject: Reply with quote
rawhead wrote:
Glassless M42-F mount adapters can do up to 17ft or so, I believe. Of course, if you stop down to f16 or 22, I think you can "almost" get infinity due to hyperfocal. (I'm talking about 50mm lenses. You might get infinity with wider angle lenses).


you will never get infinity if the register distance of the lens is shorter than that of the camera. You might obtain a decently longer DOF using superwide lenses by stopping down all the way as you said (and getting a bit of diffraction degrade as well...). But the trick will work only on small prints or the web. If you print medium-large size, the trick will show...


PostPosted: Sun Jul 05, 2009 12:46 pm    Post subject: Reply with quote
The last M42->PK mount adapter I got has a problem where, after mounting on the camera, just a slight pressure on the lens will make it continue rotating clockwise. The fix, somebody pointed out, was to use a dremel to trim one of the blades, which I haven't gotten around to, and frankly, shouldn't be necessary to do on a finished product. Has this been fixed at all, or are the ones you have basically the same ones from before?


Problem documented here:

http://forum.mflenses.com/pentax-k-m42-adapter-with-inner-flange-t16928,highlight,m42.html


PostPosted: Fri Mar 19, 2010 1:47 pm    Post subject: Reply with quote
sorry to bump an old thread, does anyone know if these, or something similar of good quality is still available?

and how close to Pentax adaptor quality are they ?

thanks


PostPosted: Fri Mar 19, 2010 2:06 pm    Post subject: Reply with quote
LittleSkink wrote:
sorry to bump an old thread, does anyone know if these, or something similar of good quality is still available?

and how close to Pentax adaptor quality are they ?

thanks


i still sell these, quality is good, but i heard that the Pentax is better, but also very difficult to get.

If you are interested, please send me a pm.


PostPosted: Fri Mar 19, 2010 5:48 pm    Post subject: Reply with quote
As I'll order some of them (alex, check your mails Wink ) I'll be able to do a fast review, I have an Asahi Pentax, and a Pentax (both originals) Wink


PostPosted: Thu Jul 01, 2010 4:17 am    Post subject: Reply with quote
I hope they're still available (Alex, I've sent you a private message). Thanks!


PostPosted: Tue Jul 06, 2010 11:17 am    Post subject: Reply with quote
As I just put into a PM to Alex does anyone know if Meyer-Optik Gorlitz lenses need this mount with the internal flange for the aperture pin or are they ok with the cheaper mount that doesn't have this internal flange Question

Also are they being supplied now with the modification mentioned or is that something that the user needs to do themselves when it turns up Question

Ta all !

Gareth
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