This tutorial show how to modify minolta lenses and use them into Canon EOS Digital Cameras.
This mod works perfectly for Canon APS-C Cameras, as they have a smaller mirror inside its mechanism.
BUT also works for Fullframe cameras if you only use the lenses for video mode, as the mirror may touch the rear elements, scratching the optics.
You can follow the steps or look the video tutorial:
Step 1: The Problem Solution
The problem with Minolta MD mount lenses on EOS Cameras is the flange distance.
Minolta MD mount distance is 43.5[mm].
Canon EF mount distance is 44[mm].
So you cannot use minolta lenses using adapter rings without a corrector glass, that allows you to focus to infinity.
EXCEPT!!! for this two ring adapters and a little modification that allows you to correct the 0.5[mm] difference, and does NOT degrade the lens quality.
This mod was tested on:
Minolta MC Rokkor-X PG 50mm f/1.4
Minolta MD Rokkor-X 45mm f/2.0
Minolta MC Rokkor PF 135mm f/2.8
But may also work in any Minolta MD mount prime lenses
Not tested on zoom lenses, as they have a different focus mechanism.
Step 2: Tools and Materials
Step 3: Permanent or Non-permanent?
This mod can be done in two ways.
The adapter ring with the flange can be ordered in two materials (steel or nylon plastic):
By ordering this ring in steel material, you can tap the little hole, so in that way you can put a removable 3mm flathead screw.
And by ordering this ring in a nylon plastic material, you can just glue the adapter ring to the minolta mount, doing this mod permanent.
The second ring is made separately because sometimes you need to file a bit to attach both rings tight and secure.
Step 4: Removing the Aperture Mechanism
- First to do this mod easier you need to rotare the aperture to f/1.4 and the focus ring to infinity.
- You will see 3 lateral tiny flat-head screw in the silver ring, you can just loosen these ones to remove the silver ring.
- You will notice 4 crosstype screw across the aperture ring, those ones secure the aperture mechanism, you can remove those.
Step 5: Modifying the Focus Internal Mechanism
As you remove the aperture mechanism you will see the focus mechanism, with a internal silver ring and the external black grip ring.
NOTE: at this point, if you own another Minolta lenses you can modify those with the suggestions in the last step of this tutorial.
- Remove the lateral flat-head screw, that provides hard-stops to the external focus ring.
- remove the 3 crosstype screw that hold the lock pin of the internal focus ring.
- remove the lock pin to allow the internal silver ring runs freely.
- Grip the external black focus ring and rotate CLOCKWISE the internal silver ring using a screwdriver until you reach the same position. (You will notice the silver ring goes inner the black ring just the enough distance to correct the focal distance).
So now you can reassembly the complete lens.
Step 6: Reassembling the Lens
- Reattach the 3 crosstype screws that hold the lock pin of the internal focus ring.
- Reattach the lateral flat-head screw that provides hardstops to the focus ring.
- Ensure the lens is focused to infinity.
- Ensure the aperture pin is on the wide-open aperture position.
- Align the focus arrow with the infinity sign and relocate the aperture mechanism.
- Reattach the four crosstype screws across the aperture ring.
Step 7: Modifying the Silver Ring
To provide a lock mechanism for the Canon EOS cameras, you should file a little trace of the silver ring that was first. As you notice in a regular Canon EF mount lens, you will see a little oval hole that attach the pin of the mount locking system.
By filing this rings you create this locking system, and you can orient this filed section in a right angle from the focus arrow on the top on the lens.
Step 8: Attaching the Adapter Rings
- Locate the nylon plastic ring first.
- Locate the metal or nylon flange ring.
- rotate clockwise the rings until the little threaded hole reach the Minolta mount lock pin.
- Attach a little 3mm flathead screw to secure the adapter rings or glue the adapter rings to the mount.
and it is DONE!.
As you see the last photos you can attach the lens aligning the red dots and turning clockwise the lens until you hear the click, of the lock system pin.
Step 9: Sample Pictures
I let you 4 sample pictures taken with this Minolta MC Rokkor-X PG 50mm f/1.4 at 1.4 and 2.0
Thanks for your time, share this tutorial will help me alot.
I will make soon a FD to EF adapter mount, that you can use to modify FD lenses to use them into EOS digital cameras!!!.
Step 10: Some Other Ideas to Modify Any Minolta Lens.
The difference of 0.5[mm] between Minolta MD and Canon EF can be corrected easily if you own other Minolta lens, you can use the adapter rings I've shown in this tutorial followed by one of these modifications:
- Rotating the internal focus mechanism as show in the tutotial.
- Filing a section of the external black focus ring, in the picture you see the focus mechanism without its flathead screw that provides the hardstops to the focus ring, you can remove this screw and rotate the focus ring and you will notice that you also reach the 0.5[mm] to correct the focal distance, BUT by rotating to the focus ring to the shortest focus distance (50[cm]) the front elements may deattach and fall damaging the lens. So you need this lock flathead screw for the focus ring, but you can file down the section needed to reach the correct focal distance.
- A more tedious way to modify any minolta lens is by filing the 0.5[mm] from the internal silver ring, where the 4 crosstype screws goes attached, in the same picture you can see that this silver internal ring supports the aperture mechanism and mount of the lens, by shortening this ring the same amount needed, you can correct the focal distance.