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The thriller starts... Converting the Planar 50mm 1.7 to M42
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PostPosted: Thu Mar 20, 2008 8:04 am    Post subject: The thriller starts... Converting the Planar 50mm 1.7 to M42 Reply with quote

Death or Glory? We'll know...
But I'm decided to try the transformation of the CZJ Planar to M42.

Yesterday arrived the parcel sent by Dennis (thanks a lot!!!) containing a full zebra CZJ 135 f/3.5 and a M42 screwed base coming from another lens. The CZJ is in not perfect shape, but it does work (I tried it on the K100DS), so I'll be trying first the M42 base, although the zebra could be a better fit, because it's the same brand and probably easier to manage.






More news soon.

Jes.


PostPosted: Thu Mar 20, 2008 9:09 am    Post subject: Reply with quote

Good luck!


PostPosted: Mon Mar 24, 2008 11:39 pm    Post subject: FIrst steps Reply with quote

Today I've reached the courage level necessary to disassemble the lens. My first try will be to break apart the mount and to rebuild it again. Just to see if I can do a reversable conversion, and to get some expertise in the process.

First I tried to disassemble the whole mount block by unscrewing the four screws around the crown:



But unfortunately it cannot be fully removed this way (it gets loose but there is something that prevents to fully extract it), so I proceeded to take out the upper elements by unscrewing the three screws on top:





This frees the small cylynder around the lower lens.



Next step is to take out the four screws on the base mount and take it out:





And now the M42 base could fit in if we would not have this protruding lever, that doesn't allow to fit the M42 base centered. Since it's a Contax only utility, I can get rid of it by cutting it (is a plastic piece). It's not used even on a digital body using the C/Y adapter. So no big loss... But I want to assemble the lens back before proceeding to any modification.
Next to the lever there is a small ball bearing that makes the clicking when changing apertures.



So next time I disassemble it I'll cut the lever and adapt the M42 base.
By now it's enough. I've seen all the moving parts and I understand their usage, so I've rebuilt the lens back.
No problems, it's a quite straightforward process following the reverse steps.

Finally, the lens up and running again, no mods yet:



Apologies for the pictures: Since most elements are black, I had to get the Caplio to the limits (reaching the aperture limit, I had to use very low speeds). Even with the shaking reduction on, at such speeds there is some trembling, and I was so obfuscated with the process that I didn't go for the tripod...

Jes.


PostPosted: Tue Mar 25, 2008 12:06 am    Post subject: Reply with quote

Very nice report! Thank you Jes!


PostPosted: Tue Mar 25, 2008 12:58 am    Post subject: Reply with quote

So exciting seeing that lens again - like seeing yourself on tv!


PostPosted: Tue Mar 25, 2008 8:24 am    Post subject: Reply with quote

nice report Jes!
if I ever buy a pentax it will be for in body IS
I would prefer to change the mount on the camera to use my contax.

Jes wrote:
there is some trembling

maybe trembling have to do with opening your 200 euros lens


PostPosted: Tue Mar 25, 2008 9:33 am    Post subject: Reply with quote

How you plan to center the new screw holes in the M42 mount?


PostPosted: Tue Mar 25, 2008 1:02 pm    Post subject: Reply with quote

kansalliskala wrote:
How you plan to center the new screw holes in the M42 mount?


Not difficult, (I hope). The M42 base seems to be of a very similar diameter than the C/Y. I'll draw a paper template from the C/Y with the current holes. The M42 base has a notch that allows alignment with the top of the camera. I'll place the M42 base over the C/Y template and mark the holes on the M42 base. If I see any centering problem, I'll place some spacers around the inner lens, to keep the ensemble centered, but I expect not needing it.

Jes.


PostPosted: Tue Mar 25, 2008 1:10 pm    Post subject: Reply with quote

You're a brave man. Shocked


PostPosted: Tue Mar 25, 2008 1:31 pm    Post subject: Reply with quote

Orio wrote:
You're a brave man. Shocked


Orio, thanks but I'm not so brave... Wink

In the first place, notice that I won't be touching the optics, just the mount. Nothing in the optics ensemble will be disassembled.
I've also evaluated the possible damages and there are none: even if I have to get back to the C/Y mount, I'd lose nothing, since the lens will still be useable on the Canon... True, I'll lose some functions if going to mount it on a Contax/yashica film camera, but I don't expect to have any of those...
I got enough SLRs in good shape (and in the refurbishing lane) to look for another body.

Tonight will be the night (hopefully).

Jes.


PostPosted: Tue Mar 25, 2008 2:55 pm    Post subject: Reply with quote

Jesito wrote:
If I see any centering problem, I'll place some spacers around the inner lens, to keep the ensemble centered, but I expect not needing it.


Rotate the template around back element so you see if holes are equally distanced and 90 angle .. ?


PostPosted: Tue Mar 25, 2008 3:06 pm    Post subject: Reply with quote

kansalliskala wrote:
Jesito wrote:
If I see any centering problem, I'll place some spacers around the inner lens, to keep the ensemble centered, but I expect not needing it.


Rotate the template around back element so you see if holes are equally distanced and 90 angle .. ?


Good idea, to see if it's centered evenly!
Thanks!

Jes.


PostPosted: Wed Mar 26, 2008 8:29 am    Post subject: Reply with quote

(No progress yesterday... let's see how comes today).

Jes.


PostPosted: Thu Mar 27, 2008 8:34 pm    Post subject: Reply with quote

Hi Jes !

How's the conversion going ?

I succesfully finished tonight my own conversion of a Yashica 50mm f2 from C/Y to Pentax K.

I was quite bold on this one because the lens cost me - 1 (minus 1 euro) Smile I bought a Yashica FX3 with that lens, a 28-200, a flashgun and a bag for 25 et sold back the 28-200 for 26 Very Happy

I'm eager to try it in the "real world" because first test shots seems promising.


PostPosted: Thu Mar 27, 2008 11:13 pm    Post subject: Reply with quote

Jieffe wrote:
Hi Jes !

How's the conversion going ?

I succesfully finished tonight my own conversion of a Yashica 50mm f2 from C/Y to Pentax K.

I was quite bold on this one because the lens cost me - 1 (minus 1 euro) Smile I bought a Yashica FX3 with that lens, a 28-200, a flashgun and a bag for 25 et sold back the 28-200 for 26 Very Happy

I'm eager to try it in the "real world" because first test shots seems promising.


Good work, Jieffe! (and good trade Wink ).

I'm quite busy this week (still audits ongoing) and I arrive too late home. Hopefully next weekend I'll finish it...
Could you post some images of your conversion?
Thanks!

Jes.


PostPosted: Fri Mar 28, 2008 6:18 am    Post subject: Reply with quote

Jesito wrote:
Could you post some images of your conversion?

I neglected to take pictures during the conversion but I will try to document "the final product" this weekend ... have to go to work now Smile


PostPosted: Sat Mar 29, 2008 3:15 pm    Post subject: Reply with quote

As promised ...

After removing the mount, I took a look at the aperture ring. It has the same lever as your lens.



I removed the metal part that is fixed underneath by 2 screws.



This means that the aperture ring won't click but I can live with that.

After, I had to find a way to link the aperture with the aperture ring.

I used a spring... not very elegant, but working.



Finally, the pentax mount coming from a broken lens. I used one existing hole and make another from the back and countersunk.
I added 2 spacers made from cardboard between the lens and the mount, otherwise, the aperture ring is blocked.



And voil?, a Pentax-K Yashica lens with infinty Smile


PostPosted: Sat Mar 29, 2008 4:41 pm    Post subject: Reply with quote

Great work, Jieffe!!

Thanks for sharing,

Jes.