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Archive 2012 · lens repair, modification and disassembly guide thread
  
 
LightShow
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p.6 #1 · p.6 #1 · lens repair, modification and disassembly guide thread


Adjusting infinity looks as hard as the G45 project.


May 18, 2013 at 04:14 AM
sebboh
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p.6 #2 · p.6 #2 · lens repair, modification and disassembly guide thread


LightShow wrote:
Adjusting infinity looks as hard as the G45 project.


harder actually, can't be done while the optics are installed. laziness won out.



May 18, 2013 at 04:28 AM
RCicala
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p.6 #3 · p.6 #3 · lens repair, modification and disassembly guide thread


These aren't really modifications - just just getting the dust out on mostly current Canon lenses. Might be useful to someone wanting to open these up, though:

http://www.lensrentals.com/blog/2013/05/a-few-easy-lens-dustings



May 18, 2013 at 10:51 AM
JimBuchanan
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p.6 #4 · p.6 #4 · lens repair, modification and disassembly guide thread


Hi All,

I'll be paying more attention to this thread, now that I finally have a G28 on the way. As mentioned upthread, I elected to use a MD 50/2 donor lens due to the smaller diameter and size, but the aperture ring is plastic.

Sebboh, So it looks like you have done a G45 already and now a G28. The 45 looks to have some type NEX adapter, maybe a Leica M bayonet?

Are you planning a M bayonet on the G28? If so, I suppose you would get proper infinity focus on a Leica M camera? minus the rangefinder focusing of course.



May 18, 2013 at 02:02 PM
sebboh
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p.6 #5 · p.6 #5 · lens repair, modification and disassembly guide thread


JimBuchanan wrote:
Hi All,

I'll be paying more attention to this thread, now that I finally have a G28 on the way. As mentioned upthread, I elected to use a MD 50/2 donor lens due to the smaller diameter and size, but the aperture ring is plastic.

Sebboh, So it looks like you have done a G45 already and now a G28. The 45 looks to have some type NEX adapter, maybe a Leica M bayonet?

Are you planning a M bayonet on the G28? If so, I suppose you would get proper infinity focus on a Leica M camera? minus the rangefinder focusing of
...Show more

yes, m-mount for both lenses as it allows me to use helicoid adapters on them for an even better mfd as well giving me more latitude as to which future cameras i use them on.

one issue for me is that i don't presently have an m-mount adapter that hits infinity dead on with leica lenses so i can't tune infinity as well as i would like. hopefully at some point i'll be able to borrow a leica m so i can set the infinity stop precisely where it should be. does anyone know if the gxr flange distance is as consistant as leica's?

for what it's worth, i examined an MD 50/2 at some point while trying to determine a good donor lens and it seemed to have internals that were less conducive to the conversion than the MC 55/1.7 in addition to the poorer construction. can't remember exactly what the issue was though.



May 18, 2013 at 02:48 PM
KOJI
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p.6 #6 · p.6 #6 · lens repair, modification and disassembly guide thread


Guess it would help someone who are interested in some conversions without a NC machine.

http://www.pbase.com/kkawakami/top_level_lens_modifications



May 18, 2013 at 02:49 PM
sebboh
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p.6 #7 · p.6 #7 · lens repair, modification and disassembly guide thread


KOJI wrote:
Guess it would help someone who are interested in some conversions without a NC machine.

http://www.pbase.com/kkawakami/top_level_lens_modifications


interesting, you keep the front part of the contax helicoid attached to the optics.

now i remember why i thought the MD 50/2. wouldn't be that good i was considering it for the g45 which has to large a rear element to fit through that rear opening and i thought linking the aperture mechanisms between the two lenses would be difficult.



May 18, 2013 at 03:38 PM
KOJI
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p.6 #8 · p.6 #8 · lens repair, modification and disassembly guide thread


Yes, I thought it was too difficult to install an aperture linkage with MD 50/2 for G-Biogon 28mm,
so decided to make double-decker lens as you see. It does not look good, but it works fine.



May 18, 2013 at 04:20 PM
JimBuchanan
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p.6 #9 · p.6 #9 · lens repair, modification and disassembly guide thread


sebboh wrote:
one issue for me is that i don't presently have an m-mount adapter that hits infinity dead on with leica lenses so i can't tune infinity as well as i would like. hopefully at some point i'll be able to borrow a leica m so i can set the infinity stop precisely where it should be. does anyone know if the gxr flange distance is as consistant as leica's?


For what it's worth, here is my reference, calibrated Leica M to NEX adapter:





The thickness looks to be .015" less than .400", or .385". The handle is 25 divisions per revolution. This is the true thickness sitting on the NEX camera. The photo shows the caliper flush against the NEX side, but this adapter has a .005" standoff lip that causes a .005" gap between the camera and adapter. So, my measurement is the true inside thickness.

When used with a Leica M camera and modern calibrated lenses, this Metabones was too thin and the lenses focused past infinity. I shimmed the adapter with I think it was .004".

This should get you in the ballpark.



May 18, 2013 at 04:44 PM
LightShow
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p.6 #10 · p.6 #10 · lens repair, modification and disassembly guide thread


sebboh wrote:
harder actually, can't be done while the optics are installed. laziness won out.

Your laziness has more done on your project than my laziness has on my project.



May 18, 2013 at 07:29 PM
 

Search in Used Dept. 



sebboh
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p.6 #11 · p.6 #11 · lens repair, modification and disassembly guide thread


JimBuchanan wrote:
The thickness looks to be .015" less than .400", or .385". The handle is 25 divisions per revolution. This is the true thickness sitting on the NEX camera. The photo shows the caliper flush against the NEX side, but this adapter has a .005" standoff lip that causes a .005" gap between the camera and adapter. So, my measurement is the true inside thickness.

When used with a Leica M camera and modern calibrated lenses, this Metabones was too thin and the lenses focused past infinity. I shimmed the adapter with I think it was .004".

This should get you in the
...Show more

thanks! just to be clear, the final distance between camera mount and lens mount that allows you to nail infinity at the infinity stop is .385"?



May 20, 2013 at 05:13 AM
JimBuchanan
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p.6 #12 · p.6 #12 · lens repair, modification and disassembly guide thread


Yes, .385". I only mention the standoff gap to give a heads up that some adapters may have a likewise gap. I didn't realize it at first, measuring the outer thickness. Then, on the camera I noticed the gap, and re-measured using the inner part of the adapter face that the camera mount contacts.


May 20, 2013 at 02:02 PM
sebboh
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p.6 #13 · p.6 #13 · lens repair, modification and disassembly guide thread


took the final frankenzeiss g28 apart today to document how the aperture linkage works.

the optical block on the g28 has a screw that links the plastic rotating flange to the actual aperture mechanism (screw directly to the left of the green star):





this screw has the same threading as the ones that held the optical block into the zeiss body, so i simply used one of those as a longer replacement screw to hold another bent christmas tree hook aperture linkage:





the other linkage was done the same way as with the g45 conversion:





here's what the finished lens looks like:
































May 27, 2013 at 02:06 AM
Edgars Kalnins
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p.6 #14 · p.6 #14 · lens repair, modification and disassembly guide thread


Nice work! Contax G are wonderful lenses, but I wondered if there are any suggestions about adapting lenses from the small compact film cameras? I have seen contax T2 and T and yashica T lenses adapted so far. Has anyone tried to put Contax T3 lens on sony nex? Supposed to be better, but seems to be a more complicated construction (due to closer MFD I guess).


May 28, 2013 at 04:44 PM
sebboh
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p.6 #15 · p.6 #15 · lens repair, modification and disassembly guide thread


Edgars Kalnins wrote:
Nice work! Contax G are wonderful lenses, but I wondered if there are any suggestions about adapting lenses from the small compact film cameras? I have seen contax T2 and T and yashica T lenses adapted so far. Has anyone tried to put Contax T3 lens on sony nex? Supposed to be better, but seems to be a more complicated construction (due to closer MFD I guess).


not sure, i've always been curious about those too but figured they probably wouldn't play well with NEX sensors.



May 29, 2013 at 12:23 AM
freaklikeme
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p.6 #16 · p.6 #16 · lens repair, modification and disassembly guide thread


Beautiful work, D. The 28's prettier than the 45, so I'm assuming you don't really need the 45 back. You wouldn't want to give it an inferiority complex, would you?


May 29, 2013 at 05:20 AM
sebboh
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p.6 #17 · p.6 #17 · lens repair, modification and disassembly guide thread


freaklikeme wrote:
Beautiful work, D. The 28's prettier than the 45, so I'm assuming you don't really need the 45 back. You wouldn't want to give it an inferiority complex, would you?


thanks! you like the silver better than the black too? maybe i should make another g45 conversion with the silver look. i took a shot out the window yesterday though and discovered the major weakness of the silver lens barrel.

i suspect my g28 feels a little out of place amongst all my rokkors though. he'd probably appreciate his big brother back at some point. have you used it much on the gxr?



May 29, 2013 at 05:56 AM
freaklikeme
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p.6 #18 · p.6 #18 · lens repair, modification and disassembly guide thread


sebboh wrote:
thanks! you like the silver better than the black too? maybe i should make another g45 conversion with the silver look. i took a shot out the window yesterday though and discovered the major weakness of the silver lens barrel.

i suspect my g28 feels a little out of place amongst all my rokkors though. he'd probably appreciate his big brother back at some point. have you used it much on the gxr?


I figured it would have some practical issues, but it's very sleek looking. It does make you wonder why Zeiss likes to put the silver rings on the modern SLR lenses.

It's mounted on the GXR now. If the sky clears up today, I'll be using it for a pano this evening. I'm thinking I should send you the GXR when I send back the 45. I bet the 28 would give great results on it. It's a good time to do it, too, since I won't have any time for my oddball third camera again until the end of the summer.



May 29, 2013 at 02:32 PM
sebboh
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p.6 #19 · p.6 #19 · lens repair, modification and disassembly guide thread


freaklikeme wrote:
I figured it would have some practical issues, but it's very sleek looking. It does make you wonder why Zeiss likes to put the silver rings on the modern SLR lenses.

It's mounted on the GXR now. If the sky clears up today, I'll be using it for a pano this evening. I'm thinking I should send you the GXR when I send back the 45. I bet the 28 would give great results on it. It's a good time to do it, too, since I won't have any time for my oddball third camera again until the end of the
...Show more

cool, that would probably solve my accurately tuning infinity for m-mount issue. i don't really have any rangefinder wides other than the g28, so i doubt the gxr would see much real world use for me. i am curious how the g45 and 40 cron compare on it to on the NEX-7 (have you tried your 35 lux on it?).



May 30, 2013 at 06:04 AM
Edgars Kalnins
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p.6 #20 · p.6 #20 · lens repair, modification and disassembly guide thread


I have been trying to adapt the Contax T2 Sonnar 38mm f2.8 on my sony nex-3. It has been done before, but it seems to me that the focusing abilities were limited or sacrificed for simplicity or other considerations. So far I have only attached the lens temporarily to check the quality of images. My skills being as they are I ended up removing the mount plate from my sony camera and selotaping the lens onto it! Close-ups look satisfying to me and I will update once I have some images at infinity.

Forgot to switch from jpeg to raw, so the pictures are just standard jpeg improved in Lightroom.

Contax T2 lens on Sony nex-6 by lowlightlove, on Flickr


Contax T2 lens on Sony nex-3 by lowlightlove, on Flickr

Edited on Jun 12, 2013 at 09:19 AM · View previous versions



Jun 12, 2013 at 08:57 AM
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