Minolta Rokkor 50mm MD f1.4 Aperture ring is loose

[Jim Schemel]

I have successfully converted a Minolta Rokkor MD 50mm f1.4 to EOS mount.I am able to achieve infinity focus as well.Only problem that i have run into is the aperture ring does not click into position and it does not stay open at 1.4 it is very loose, the aperture ring the blades an all work fine no problems there.It just needs to be held open and thats no fun.My Rokkor 45f2 clicks into each aperture position.Does any one know what is wrong with this? Likely a ball bearing or something that i am just not seeing.
-Jim

[cooltouch]

It's been many years since I've dismantled a Rokkor lens, but often there is a small ball used for aperture ring detents. Could it be you left it out when re-assembling the lens?

[Jim Schemel]

Very good chance.I'm just not sure where it goes, to put something else in there to see if i can get it to work.
-Jim

[cooltouch]

Often, the ball will be located in a small hole with a spring located beneath it. The aperture ring detents run across the top of the ball -- the ball itself doesn't move from its position. That's at least one way it's done.

[sven_hiller]

There is a chance that the spring is still in the hole. I have seen some examples of Rokkors that had some grease around the spring and in the hole. So the ball came out when disassembling but the spring still kept sitting in there.
Don't know if it is the right size, but I think as a spare part the tip of a ballpoint pen could possibly do.
When reassembling use thin adhesive tape that you can pull out after the aperture ring is in place.

[Jim Schemel]

Sven,
Yes the spring was still in there.And i was able to use a ball bearing from an old camera shop.so far so good.
-Jim