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Looking for a damaged M42 lens
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PostPosted: Thu Mar 06, 2008 11:00 pm    Post subject: Looking for a damaged M42 lens Reply with quote
Hi colleagues!

I'm thinking to convert my Zeiss Planar to M42, so I'm looking for a damaged M42 lens that would act as a donor.
You know my (maybe) strange conception of life: I would not use a functional one, even extremely cheap. (I've found Helios 44-2 very cheap, but useful!).

The ideal candidate should be a broken lens beyond repair, that has an useable M42 base fixed by screws.

So if any of you have such a broken lens, and thinks in throwing to the wastebasket, please don't do that!.

I would pay the shipping costs, and I promise to write a tutorial to show how I did (succeed or fail). Unlimitted beers included at the time we could meet.

Thanks in advance!.
Jes.

I must insist, no way with useable lenses... (I devote much time to repair things, so I won't break anything functional for any reason).


PostPosted: Fri Mar 07, 2008 12:51 am    Post subject: Reply with quote
I would love to give you, but I don't have any broken lens Sad


PostPosted: Fri Mar 07, 2008 1:04 am    Post subject: Reply with quote
Hi Jesito,

I think I have one or two M42 broken lenses. I don"t remember if they could be usefull for such purpose (some lenses are not because the mount is part of the barel, as some Takumars).

I will take pictures of the mount this week-end.

Cheers


PostPosted: Fri Mar 07, 2008 5:48 am    Post subject: Reply with quote
Thanks a lot to both of you!.

I have to make my mind. Disassembly my beloved Planar scares me, but I couldn't give up and let it aside. I cannot afford to live without using it on the Pentax and on all the other film cameras...

So not really in a hurry Wink

Thanks again!.

Jes.


PostPosted: Fri Mar 07, 2008 6:59 am    Post subject: Reply with quote
I have several here, I may have a couple of options for you, what is the diameter of the rear of the planar?


PostPosted: Fri Mar 07, 2008 7:42 am    Post subject: Reply with quote
hacksawbob wrote:
I have several here, I may have a couple of options for you, what is the diameter of the rear of the planar?


Thanks a lot Bob!.
I really don't know now.
It has been a thought decission. I was always sadly looking to my Planar (the one with I've taken my best shots) sitting in the drawer. At first I didn't want to do any "bricolage" on it, but after watching at the mods shown at Pbase one thousand times, I've got enough courage to dare trying...

Tonight I'll mesure it , as soon as I get home.
Thanks again!.

Jes.


PostPosted: Fri Mar 07, 2008 8:03 am    Post subject: Reply with quote
Have you thought making drawings of the part and asking what would it cost in some small metal shop. I know it can't be more than 15 minutes lathe work to make the base and another 15 minutes drilling.


PostPosted: Fri Mar 07, 2008 8:30 am    Post subject: Reply with quote
kansalliskala wrote:
Have you thought making drawings of the part and asking what would it cost in some small metal shop. I know it can't be more than 15 minutes lathe work to make the base and another 15 minutes drilling.


Hi Kansalliskala!
Thanks for your suggestion, but I don't know any metal shop here...
(I'm not proficient in mechanics, I barely know what a lathe is Sad )

Jes.


PostPosted: Sat Mar 08, 2008 12:54 am    Post subject: Reply with quote
hacksawbob wrote:
I have several here, I may have a couple of options for you, what is the diameter of the rear of the planar?


Hi Bob, the diameter is 62mm in the outside, and 58mm at the base mount. An image is worth 1000 words...



Thanks!.

Jes.


PostPosted: Sat Mar 08, 2008 2:43 am    Post subject: Reply with quote
I have a Carl Zeiss 135mm f3.5 (zebra) with an M42 mount which is mounted with screws. There's significant damage to the front and I have a later version now (the swap with the Soligor 135mm f2.8 NAI succeeded!) so I don't need this one. Any help? I'll try and post a picture tomorrow.


PostPosted: Sat Mar 08, 2008 8:03 am    Post subject: Reply with quote
The back element just fits about 35 mm inner tube of the m42 mount? What you planning to do with the aperture lever?


PostPosted: Sat Mar 08, 2008 8:07 am    Post subject: Reply with quote
Puplet wrote:
I have a Carl Zeiss 135mm f3.5 (zebra) with an M42 mount which is mounted with screws. There's significant damage to the front and I have a later version now (the swap with the Soligor 135mm f2.8 NAI succeeded!) so I don't need this one. Any help? I'll try and post a picture tomorrow.


Thanks, Puplet!. I wait for your picture...

Jes.


PostPosted: Sat Mar 08, 2008 8:12 am    Post subject: Reply with quote
kansalliskala wrote:
The back element just fits about 35 mm inner tube of the m42 mount? What you planning to do with the aperture lever?


I'll try to follow these detailed (and I think simple) directions from an article in Pbase:

http://www.pbase.com/wesleywong/image/53046607

I was using it with a Y/C to EOS adaptor, where the aperture lever remains inside the adaptor and is not used. (Full manual mode). I'll try to remove it if necessary and use the lens in manual mode, turning the aperture ring to wide open for metering, as I do with most of the M42 lenses.

Jes.


PostPosted: Sat Mar 08, 2008 11:08 am    Post subject: Reply with quote
Here you go - any use?





PostPosted: Sat Mar 08, 2008 11:30 am    Post subject: Reply with quote
Puplet wrote:
Here you go - any use?




I think so!.
This screwed piece in top is just what I do need!!
(Are you sure the lens is damaged beyond repair?.)

Thanks!
Jes.

Last edited by Jesito on Sat Mar 08, 2008 1:15 pm; edited 1 time in total


PostPosted: Sat Mar 08, 2008 12:00 pm    Post subject: Reply with quote
Hole for the back element looks kind of small, could be even less than 35 mm?


PostPosted: Sat Mar 08, 2008 1:14 pm    Post subject: Reply with quote
kansalliskala wrote:
Hole for the back element looks kind of small, could be even less than 35 mm?


It's just 35mm in the Planar, so if the hole is less it won't fit...



Jes.


PostPosted: Sun Mar 09, 2008 9:29 pm    Post subject: Reply with quote
what lens mount is that? is it CY?


PostPosted: Sun Mar 09, 2008 9:40 pm    Post subject: Reply with quote
hacksawbob wrote:
what lens mount is that? is it CY?

Yes, it's a C/Y.

Jes.


PostPosted: Sun Mar 09, 2008 10:25 pm    Post subject: Reply with quote
I have a solution for you that is quite easy, I think it will work. Mount the tessar rear through a CY rear lens cap. requires cutting a hole in the lens cap and grinding down the tessar rear mount so it sits inside it. there may be just some clearance issues internally with this as CY and M42 are the same registration you will loose the thickness of the lens cap (1mm?)


PostPosted: Sun Mar 09, 2008 11:06 pm    Post subject: Reply with quote
hacksawbob wrote:
I have a solution for you that is quite easy, I think it will work. Mount the tessar rear through a CY rear lens cap. requires cutting a hole in the lens cap and grinding down the tessar rear mount so it sits inside it. there may be just some clearance issues internally with this as CY and M42 are the same registration you will loose the thickness of the lens cap (1mm?)


Hi Bob, I'm afraid I don't follow you.
I need a M42 screw on the CZJ Planar 50mm 1.7 that now has C/Y mount on it, for using on a M42 body (I understand you said Tessar instead Wink).
I do not see how I could get the M42 from a rear cap, (apologies, my english is quite limitted..). What I'm trying to do is to cannibalize a broken M42 lens screw and put it in place of the current C/Y.

Thanks for pointing out that C/Y and M42 have the same register distance, (I didn't know it before). This would make life easyer.

Jes.

Jes.


PostPosted: Mon Mar 10, 2008 8:30 am    Post subject: Reply with quote
You need something like this:



where
A = D + thread lenght you want
B = 58 mm
C = 35 mm or more
D = the thickness of the original +- difference in reg. dist.
E = M42.-1
F = distance of holes center / 2
G & H = screw size


PostPosted: Mon Mar 10, 2008 1:25 pm    Post subject: Reply with quote
Sorry if I did no make clear enough. The Tessar rear mount which I have hase the M42 screw thread on it. The rear lens cap has the CY mount on it, you need to mount these two together so you have a M42 to CY adapter. which you can leave you beloved planar as it is. However as the mounting will possibly add 1mm to your register distance you will lose some infinity focus. If you like I can try to make this mount for you.


PostPosted: Mon Mar 10, 2008 2:48 pm    Post subject: Reply with quote
hacksawbob wrote:
Sorry if I did no make clear enough. The Tessar rear mount which I have hase the M42 screw thread on it. The rear lens cap has the CY mount on it, you need to mount these two together so you have a M42 to CY adapter. which you can leave you beloved planar as it is. However as the mounting will possibly add 1mm to your register distance you will lose some infinity focus. If you like I can try to make this mount for you.


Oh, I see now, thanks a lot!!.
Dennis has already sent me a broken lens, so let me try first the conversion. I understand dismounting the back mount will not damage the lens. Since I got M42 adapters for all my cameras,once I do the change I don't see any reason to keep the C/Y mount anymore. (I could only mount it on the 350D through an adapter).
But thanks anyway, I appreciate very much your suggestion (now that I understand it Wink). I'd prefer not to lose the infinity focus.

I'll keep posting on the evolution.
Jes.


PostPosted: Mon Mar 10, 2008 2:51 pm    Post subject: Reply with quote
kansalliskala wrote:
You need something like this:



where
A = D + thread lenght you want
B = 58 mm
C = 35 mm or more
D = the thickness of the original +- difference in reg. dist.
E = M42.-1
F = distance of holes center / 2
G & H = screw size


Hi Kansalliskala!, you're good on Autocad, aren't you?. Wink
Thanks for the details. If I need to modify the broken lens that Dennis has sent to me, I'll use this drawing!.
Thanks a lot!
Jes.
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