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Since the question of how to convert various Minolta MC/MD lenses to Canon EF mount comes up regularly, I thought I would post a bit about what I have done recently.
Some months ago while browsing for info on Minolta lenses, I came across a post with a different method for conversion. It required some minor machine work. But, my company happens to have a large machine shop so I could trade favors with a machinist friend. I am a computer server/network administrator/manager, not a machinist.
This link shows the basic steps on how to machine an M42 adapter to fit over a Minolta MC/MD mount. That gave me some ideas on how I could improve on it.
Note, this conversion can be done with ANY Minolta MC/MD lens. Minolta varied the details on just about every lens, but there were several designs with variations.
Here are four lenses that have been converted.
- 28mm f2 MC W Rokkor
- 24mm f2.8 MD (not quite finished)
- 58mm f1.2 MC Rokkor-PG
- 85mm f1.7 MC Rokkor
The very basic steps:
- Start with an M42 to EOS adapter.
- The machinist uses a lathe to cut off the flange plus another .5mm.
- The inside of the adapter is cut to match the Minolta mount. The fit should be tight and even at the bottom.
- Remove the Minolta mount from lens and remove about .010" from the edge of the Minolta mount that will mate with the Canon camera mount.
- Machine off the "ears" of the Minolta mount so they are even.
- Create cut outs in the M42 adapter for the Minolta screw holes so you can still disassemble the lens if needed. I use the small sanding drum on a Dremel.
- When the M42 mount is fit over the Minolta mount, the center of the Minolta mount may protrude, I sand it off level.
- Glue the machined M42 adapter to the Minolta adapter with the correct orientation. I use 3 small drops of Super Glue.
- Cut a small notch for the camera lens locking pin. I use the Dremel with a cutter, not a drill. Be sure to make the sides vertical or the lens might rotate.
Now it is done. There is no sanding or drilling holes in the adapter, big pluses for me!
Infinity focus should be close, but I usually have to adjust it using the lens' adjustment mechanism.
For someone that likes to do DIY projects, this is not hard at all. But, unless there are interesting lenses to convert there is no point.
The 58mm and 85mm are discussed elsewhere in the forum.
My very brief test shots with the 24/2.8 and 28/2 show them to be excellent so far with good coverage into the corners but I need to do some real world shots. Both have floating elements. I particularly like the 28/2.
Some possible other interesting wide angles are the 20/21mm, 17mm, 16mm fisheye and 24mm VFC. Unfortunately you have to irreversibly modify the lens before you can put it on your camera and evaluate it's quality.
So, this is just another option for people that may want to convert Minolta manual focus lenses.
Edited on Sep 22, 2008 at 07:16 PM · View previous versions