In this instructable I will convert a standard Canon EFS 18-55mm. kit lens to EF mount.
Why? Because I can, and because I have a Canon 10D laying around, and not many EF lenses. The 10D has a APS-C sensor, but it is not possible to fit EF-S lenses on it. Any later models will fit the EF-S lenses just fine because of the APS-C sensor, the 10D will work just fine with EF-S lenses, when you have modified the mount.
I'm sure you could mod other lenses aswell.
When you have modded your lens, it will be possible to also use it on full frame DSLR's aswell. If you put an EF-S lens on a full frame camera, there will be heavy vignetting. Just sayin'.
As always, it is not my fault if you break your lens or camera.
Step 2: Items You Need.
A small phillips-head screwdriver. And I do mean small.
A small hobby hacksaw.
A flat file.
Some sandpaper. Grit 100 or higher.
Some good epoxy glue.
Step 3: Step 1: Removing the Mount.
Turn your lense upside down.
Remove the 6 screws. 4 is on the bottom, and 2 is holding the electronic contacts from the side.
Gently lift the mount straight up.
Step 4: Step 2: Sawing...
First you will remove the rubber ring on the mount, then saw off some of the mount. Look at pic 6, where the red arrow is, that is where you want to cut.
Make sure you only saw thru the first layer. You need the part you saw off later, so don't do it all the way thru. Look at pic 7, this is what you want.
Step 5: Step 3: Modify the Mount to EF.
Look at pic 8, 9 and 11. Make your marks here. The small part in between the marks is what you want to save. (sorry about the jumps in numbers on the pics)
Now it is time to use your file. Look at pic 12 and 13, this is what you want. Just file away. The overlapping plastic will just fall off, when you get flush with the mount.
Now it is time to file on the edges of the plastic, so you can slide the lens in place. Look at pic 14.
Give it a good rub with your sandpaper.
If you would reassemble it now, it would work. However some electronics would be exposed.
Now it is time to take the piece you sawed off. You need to file it abit to make it fit in the EF mount. The outer measurements needs to be 38,5 mm. You only file of like 0,3-0,4 mm. Next to do, is to lay it on the table, and file 1 mm. off the top. Also you will file away the ledge that is in the middle, so the glass lens can clear it.
Now just remove all dust. Then put the sawed of piece into the EF mount, from the bottom. Then mix your epoxy glue well, and glue it. DO NOT USE CYANCRYOLATE GLUES! Aka. fast setting superglue. It gives off vapors that will settle on your lens.
Now just re-assemble everything and you are DONE!
Step 6: IT WORKS!
Just to prove that it works, here's a vid where I am triggering the aperture blades with a Canon 10D.