Topic: The Sigma/ Minolta to Canon EOS, 600mm mirror project
I REALLY must be a glutton for pain. I bought this Sigma 600mm mirror for Minolta MD off the bay, paid (I think) too much. Not only that, shortly thereafter, I bought the black one, much cheaper. These are both Sigmas, but different in design, both 600mm F8
I decided to convert them from Minolta MD to Canon EOS, but I've kept all the Minolta stuff intact, so someone can convert them back if need be. I calculated that I needed about .28" spacer to replace the original ring. The pix of both lenses shows the original parts, nothing to that.
I found some washers at the local, called "flat plate", big thick'uns. They measure about .032" shy of what I needed, but I figure one of two things:
I can afford to give up some short focus, much better to "over" infinity, and I can shim it with a number of materials, I have some shim stock, coke cans, and plastic. easy
In the pix below, the left washer is one of the originals. I just chucked the OD in the lathe, and hogged out the center hole to clear the rear element, then chucked into the center hole and cut down the OD.
Last pix shows the washer sitting into the recess in the rear of the lens. I'll use the original spacer for a pattern to drill through this new spacer, screwing the new spacer to the lens with original screws. I'll drill the import M42-to Canon EF adapter around the inner boss to clear 2-56 screws, then drill the spacer and last, tap them into the washer
Last edited by 440roadrunner (2008-08-26 06:13:39)