Canon FD mount lenses and equipment
Once upon a time, long ago, I came close to buying a Canon AE-1 film camera.
But I didn't, and then time rushed by, and now I am (like any sane person)
shooting digital. And all the old Canon FD mount gear is getting sold for
bargain prices (the owners are perhaps amazed that they can sell it at all).
Many of these old manual FD mount lenses are superb.
For studio and macro shooting, they offer essentially no
disadvantages over modern and much more expensive lenses.
In my case, I happen to have a couple of Canon FD mount bellows,
and an adapter to couple them to my EOS digital DSLR.
With that setup, I can put any FD mount lens on the front of the
bellows and go to town.
I have the 50mm f3.5 SSC macro.
It seems to perform very well, especially reversed.
I also have a couple of 200mm lenses. I have an "old style" 200mm f4 lens
which I am told has 6 elements in 5 groups. I also have the respected
200mm f4 macro lens, which has 9 elements in 6 groups (and the SSC coatings).
I was curious about the element count, because I wondered if it was simply
the same optics with a different mechanical system, but clearly it is not.
Look at this! An entire site dedicated to FD equipment.
Modifying an FD lens to fit on an EF body
Adapters can be purchased, but the problem is lens registration distance.
Due to the thickness of an EOS camera body, an FD lens is held too far away from
the focal plane (by about 2mm) to focus at infinity.
This is not an issue for a lens which will only be used for macro work, but if
an FD lens needs to focus at infinity, there are two options.
One option is to add some kind of negative lens to the adapter.
Adapters like this are available, but they have three drawbacks.
The biggest one is that being part of an inexpensive adapter
this will be a cheap lens, with significant image degradation.
Even if we ignore that, the lens is effectively a teleconverter which
yields about a 1.25x increase in focal length and about a 1 stop loss
of speed. Part of the attraction of using certain of the FD lenses is
that they are fast primes and this loss of speed is a big drawback.
The other option is to do some serious modification of the lens itself.
A number of people have described ways to do this. It is a lot of work, and
to really do it right requires a metal working lathe and the skill to know how
to use it.
I have to point out that Markus Keinath has a superb page with lots of information on
DIY camera repair and modification:
Markus mentions that Minolta SR mount lenses are much easier to convert to Canon EF
and gives these instructions about
how he did this with a Minolta 58mm f/1.2.
This lens has 4 infinity adjustment screws that allow the helicoid to be carefully trimmed into exact infinity focus.
Jim Buchanan on the Fred Miranda site sold a kit for converting this lens for $57 in 2009 on the Buy and Sell Forum.
The process goes pretty much like this:
- Get your hands on an EF lens bayonet mount.
An EOS to M42 adapter from Ebay is a good bet.
- Realize there will be no automatic aperture control.
- Protect the rear lens element.
- Remove the screws holding the bayonet ring and remove the ring.
- Carefully lift out the aperture control mechanism (watch for loose bearing balls)
- Remove the FD detent locking device.
- Remove 4 screws and remove the FD mount ring (watch for a tiny spring and bearing)
This spring is what provides aperture click stops.
- Use a lathe to remove 2mm of metal from the FD mount ring.
The ring may need to be mounted to a jig to accomplish this.
- The screws that hold this ring may need to have their heads machined thin also.
- The EF lens mount may also be thinned to accomplish the 2mm reduction needed.
- The trickiest part is to connect the aperture setting ring in some way.
- You will probably need a spanner to remove baffle rings
- Remount the aperture ring and thinned retaining ring with the thinned screws.
- Epoxy the EF mount to the thinned ring.
Drop me a line!
Tom's Mineralogy Info / firstname.lastname@example.org