p.14 #1 · lens repair, modification and disassembly guide thread
LightShow wrote:
It sounds like it's worn out, if the spindle is still good, you may be able to fill the hole and re-drill the axle hole, I assume it's plastic, so an epoxy should work, and the drill bit should be available at a hobby store if it's real tiny.
Or... This sounds like a prime opportunity for a transplant, I don't know if there is an updated set of design drawings for the rings, maybe sebboh will respond.
Maybe if there's enough interest, a new batch of rings could be made with offset mount holes for the 6bit.
sebboh wrote:
I updated my design to make the rear ring thicker, didn't do anything about offsetting mount holes. if people are interested in ordering another batch i can make that mod.
Good stuff, I somewhat surprised there isn't a lineup to convert the G45.... There's not much out there in its class.
MAubrey wrote:
On another note, for removing the front element, you'll need a spanner wrench, not a rubber tool. There are notches in the front name plate for the wrench. Moreover, if the 80-200L is like the 85L and the 135mm f/2, then that plate is glued in place. You'll need to apply acetone to dissolve the glue.
sebboh wrote:
I started out using spanner wrenches for this but found the rubber ring to generally work better and be less likely to leave a mark on the notches in the retaining rings or nameplates. where do you apply the acetone? is the glue on the front surface of the ring instead of underneath?
I'd be very careful with acetone, it's so easy to damage things with it.
p.14 #2 · lens repair, modification and disassembly guide thread
LightShow wrote:
I'd be very careful with acetone, it's so easy to damage things with it.
It certainly can. But when you're working with a lens that's otherwise a completely lost cause. My own experiments with repair have been more about teaching myself something than serious attempts to restore a valuable lens.
It's more like: "Well, if this doesn't work, that's fine. And if it does, hey that's a bonus!"
p.14 #3 · lens repair, modification and disassembly guide thread
MAubrey wrote:
It certainly can. But when you're working with a lens that's otherwise a completely lost cause. My own experiments with repair have been more about teaching myself something than serious attempts to restore a valuable lens.
It's more like: "Well, if this doesn't work, that's fine. And if it does, hey that's a bonus!"
I concur. I ve been in the same place with my first lens. A takumar 200 4 that had cost me all of $14 and now has been blessed with new lease of life, and I with confidence in my abilities. ..
p.14 #4 · lens repair, modification and disassembly guide thread
LightShow wrote:
It sounds like it's worn out, if the spindle is still good, you may be able to fill the hole and re-drill the axle hole, I assume it's plastic, so an epoxy should work, and the drill bit should be available at a hobby store if it's real tiny.
Or... This sounds like a prime opportunity for a transplant, I don't know if there is an updated set of design drawings for the rings, maybe sebboh will respond.
Maybe if there's enough interest, a new batch of rings could be made with offset mount holes for the 6bit.
Thanks for the suggestions! I'm not sure if the axle is supposed to be cemented into the hole, but re-drilling might do the trick. I'll try and play around with it soon. (Unless someone wants to sell their focus mechanism for the G45... )
Otherwise, I agree that a transplant would be a great idea. Please let me know if you put together a group order for the rings. I'll probably go for it if the price is similar to that of the last order.
p.14 #5 · lens repair, modification and disassembly guide thread
kevko wrote:
Thanks for the suggestions! I'm not sure if the axle is supposed to be cemented into the hole, but re-drilling might do the trick. I'll try and play around with it soon. (Unless someone wants to sell their focus mechanism for the G45... )
Otherwise, I agree that a transplant would be a great idea. Please let me know if you put together a group order for the rings. I'll probably go for it if the price is similar to that of the last order.
The axel could be fixed to either the housing or to the gear, in reality, it probably doesn't really matter so long as it stays in its proper place.
I doubt I'll reuse my G45 body, I'm hesitant to let it go, ask again if the fix fails.
p.14 #6 · lens repair, modification and disassembly guide thread
Trying to resurrect the discussion on the Contax G to M modification. Is it rangefinder coupled? I tried locating Jieying USA on Ebay, but I can't seem to locate him or any contact information for questions.
p.14 #7 · lens repair, modification and disassembly guide thread
LizWangPhotog wrote:
Trying to resurrect the discussion on the Contax G to M modification. Is it rangefinder coupled? I tried locating Jieying USA on Ebay, but I can't seem to locate him or any contact information for questions.
the one i show in this thread is not.
it's something easy to add to the g45 conversion (if you have an m240), but not any of the other focal lengths.
p.14 #8 · lens repair, modification and disassembly guide thread
You will not find too many rangefinder coupled G to M conversions. This uses a Hawk helical, which I have long since sold. I understand he is now selling a DYI kit for the G45 Planar for about $500. _MG_5640.jpg by jim_buchanan, on Flickr
p.14 #12 · lens repair, modification and disassembly guide thread
We should have ordered more, I somehow doubt there will be any, I won't part with my G45.
I still have the G28 rings that I haven't yet put to use, though I should get around to soon before the G28's price rises.
p.14 #13 · lens repair, modification and disassembly guide thread
LightShow wrote:
We should have ordered more, I somehow doubt there will be any, I won't part with my G45.
I still have the G28 rings that I haven't yet put to use, though I should get around to soon before the G28's price rises.
Yeah, I love the results from my G45 but am using a cheap eBay adapter and the lack of focussing accuracy is driving me nuts - such a short focus throw.
It's a bit pricey, but I guess that's the going rate. You will need to call to find out if he still has it in stock.
He has the G45 lens, still with the G mount, I don't see any conversion rings, or converted lenses, which is what Paul is after.
And yes, the G lenses are no longer cheap.
An option is to 3D print the rings, though I have no idea what the final product will be like.
p.14 #16 · lens repair, modification and disassembly guide thread
LightShow wrote:
He has the G45 lens, still with the G mount, I don't see any conversion rings, or converted lenses, which is what Paul is after.
And yes, the G lenses are no longer cheap.
An option is to 3D print the rings, though I have no idea what the final product will be like.
Ah, I missed the "rings" part. Oh, well. Maybe someone else was looking for the lens.
p.14 #17 · lens repair, modification and disassembly guide thread
i finally got around to converting my g90 to a proper helicoid, this time in e-mount rather than m-mount. figured i'd give a brief description of what i did.
i followed a similar method outlined by koji kawakami here, however i left the contax g helicoid intact rather than cutting off the bottom portion of the interior of the helicoid and i inserted the intact piece into a donor helicoid to be secured with set screws rather than an m39 to m42 adapter.
for the donor helicoid i used a leica zooan helicoid, which can be found cheaply on ebay. it fits the size of the g90 wonderfully (though not the color), is very smooth, and has 350 degrees of rotation. unfortunately the distance scale will be off as it is designed for a 135mm lens.
the contax g 90mm can be disassembled the same way as the g28 and g45 discussed earlier in this thread – you remove the nameplate to get access to 4 screws that allow the optical block to be removed including the aperture assembly. in order to to remove the front part of the g90 helicoid, one has to remove all the screws on the side of the lens body including one that is hidden under the black plastic piece that conceals the AF gearing near the base (you do not need to remove the mount!). with these gone you can remove the exterior shell of the lens which gives access to focus stops so that you can advance the helicoid till the front part is free.
the front part of the g90 helicoid happens to fit nicely into zooan helicoid: http://c2.staticflickr.com/2/1613/25338202961_c4556a60a9_o.jpg
the front of the zooan has a little ring on the front that pops off to reveal three set screws that hold the distance scale to the actual helicoid. i removed these set screws, drilled all the way through the helicoid in those holes. and tapped it for 0-80 screws to allow large set screws that will also hold the piece from the g90 in place: http://c2.staticflickr.com/2/1670/25312836842_7462a3705c_o.jpg
i then replaced the front ring on the zooan and added some indents for aperture click stops (will make them bigger with a file later): http://c2.staticflickr.com/2/1685/24804470383_0727a3daa0_o.jpg
in order for the aperture ring to sit smoothly on top you need to file off a few protrusions to that the side facing up in the following image is even all the way around: http://c2.staticflickr.com/2/1620/25431170085_42f87cbb2f_o.jpg
the piece of the g90 shell that goes on next also requires the filing down of its three legs so it can sit directly on top of the aperture ring: http://c2.staticflickr.com/2/1499/25338203451_e57d31bcb8_o.jpg
once that piece fits nicely on top of the aperture ring you can place optics in the lens and link the aperture ring to the aperture. once that is done you need to put the front ring (with the filter threads) on the lens. this will probably need to have a 1 or 2 millimeters shaved off the back end (non filter thread side) in order to sit flush against the optical block.
now you have a fully assembled lens with real manual focus helicoid and an m39 mount. unfortunately it won't quite reach infinity with the m39 mount, so i recessed the m39 threads inside an e-mount to get infinity. i used an e-mount to m-mount adapter that attaches the m-mount via set screws in the throat: http://c2.staticflickr.com/2/1663/25431170335_085efe3f7f_o.jpg
i took out the female m-mount and stuck the m39 mount through the e-mount throat. i then drilled holes in the m39 mount so i could hold it in place with the three screws in the e-mount: http://c2.staticflickr.com/2/1695/25312836582_42592a5dcc_o.jpg
i haven't seen any optical issue with those exposed screws but i'll probably cover them up with flocking...
anyway, that's it. it sounds complicated as i've described it, but is pretty simple if you're looking at all the pieces, should have shot before after pictures of everything i did...
p.14 #20 · lens repair, modification and disassembly guide thread
Beautiful!
I'll be checking this out.
I shoehorned a Nikon 105/2.5 lens assembly into a Minolta 135 lens, just to get the focusing direction to my liking, but the extra length body of 135 vs 105 helped with the Sony E short register without any adapters.
