Are Minolta SR mount lenses adaptable to Canon EOS DSLR camera bodys?
Yes and No:
The lower images are made after adapting / converting the lens to Canon EF mount - the can still be used on the old Minolta cameras - but without automatic iris operation.
There is not the very easy way like with M42 lenses. But there is a way:
The Minolta MD, MC, PF lenses with their SR mount could be adapted to Canon EOS EF mount bajonett.
But infinity may be a bit off - the register distance for Minolta SR is 43.5mm and 44.0 mm for Canon. But at least on the few testet lenses this could be adjusted easily with the lens infinity stop.
The Minolta SR mount to Canon EF mount adapter, to adapt Minolta MC, MD and most likely PF lenses to Canon EOS DSLR and film bodys:
In front you see the screw to lock the adapter to the lens mount. It is possible to make such an adapter with a kind of spring steel to lock this.
Here a bit more detailled what modification has to be done for the lens - on the Minolta MD 100mm/4 Macro lens:
The back of the lens has to be removed to make the changes reversible. The iris lever has to be removed, for this the three parts on the right has to be disassembled.
The lens mount part need a stop hole for the Canon EOS mount locking pin of the lens release button.
Here you see the old Minolta MD lens with the Minolta-Canon adapter installed. Now it can be used on Canon EOS cameras - without or near infinity.
To get exact infinity one need to adjust the infintiy setting of the lens. For this the rubber ring has to be removed. Under it you see a tape!
Remove the tape, and you could adjust the infinity setting of the lens - viewing and photgraphing an contrasty structured object at large distance (100x focal lenght is most times fair enough, 1000x focal length is good). Use a new tape afterwards.
Not the lens is usable on Canon EOS cameras - and the adapter can be reinstalled, and the lens can be used on old Minolta cameras - with a bit deadjusted infinity and no automatic iris operation.
The Minolta MC W. Rokkor 28mm 1:2.0 lens (55mm filter diameter) is also tested with my homemade Minolta Canon adapter - it works fine.
Infinity adjustment is made the same way like on the Macro Rokkor.
For infinity on the Canon EOS 5D DSLR camera I had to file the last SR mount surface a bit.
In case the conversion / adaption process doesn´t need to be reversible, the iris lever could probably be removed without open the lens back.
The very positive about this kind of adapting (with some conversion or modification of the lens):
Ther is no need to file / mill 0.5 mm of the lens away. This is somethimes done inaccurate, without proper tools - and so the image and lens main planes are no longer parallel - they are tilted.
Furthermore there is no need to think how the inner iris leverage is made usabel without lens back.
Good upcycling :-)
I am not the first one who did this: h^3 on the German DSLR forum made such an adapter two years earlier for a crop DSLR.
I got the idea doing it this way after I have converted a Minolta MC Rokkor 58mm 1:1.2 with the common way and a Minolta MC W. Rokkor HH 35mm 1:1.8. Long time after these conversions I had some Minolta Rokkor lenses, these 28/2.0, 100/4, 50/1.4 and some others, and thought if there could be an easier way.
I am going to produce some more of these adapters, most likely with a spring steel part instead of this screw. I have more old non-AF Minolta lenses I want to hack to use it with these adapters. So next step is probably a 3D design of this lens to have it produced at a CNC workshop, instead of my own small micro-mill and lathe.