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Old 29-12-2008, 07:29 PM
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bojan is offline
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,465
Canon FD lens conversion

Some time ago I promised to describe my way of converting Canon FD lens to EOS mount..
Here it is:
The lens I converted was Canon 50mm F1.4 S.S.C.
First, I removed everything that has anything to do with FD mount. This was done by removing 3 screws (they can be reached by rotating the locking bring, between the bayonet cut-outs).
For adaptor, I used one of M42-EOS adaptors (from ebay, ~$10.00) and machined it like shown on image, to be able to reach the focus of my 400D... the depth of cut was 1mm (still 1m left on adaptor, more than enough). Since this is still ~0.7mm out of focus, the focus stop had to be adjusted as well. To reach it, I had to remove (unscrew) the plastic ring with letters from the front of the lens, using a rubber tool that made good contact with the ring and yet no contact at all with the glass of the lens. Then there are two other rings to remove, before the focus stop was available. The dismantling procedure is clearly illustrated on the pictures.
The focus stop is a small curved plate, 15mm long, tightened to focuser with 3 small screws. There are a number of redundant threaded holes on each side (we need those that are to the right), so it is easy to move this stop significantly without a need of any machining.
(I moved it ~12mm, to the next set of threaded holes).
To have a control (manual, of course) over aperture, I cut a piece of brass shim, and adjusted it such that the iris is fully opened when f-ring is set to 1.4.
And this is it.. I also machined a spacer (aluminium) to cover a gap between the lens and adaptor.
Now I am looking forward to do star tests :-)
Attached Thumbnails
Click for full-size image (EOS_adapter_back.jpg)
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Click for full-size image (EOS_adapter_front.jpg)
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Click for full-size image (FD_dismantled_front.jpg)
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Click for full-size image (FD_lens_back.jpg)
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Click for full-size image (FD_lens_back_spacer.jpg)
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Click for full-size image (FD_lens_dismantling_font_2.jpg)
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Click for full-size image (focus_stop_moved.jpg)
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Click for full-size image (finished.jpg)
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