Please help... "Rusty" 50mm 1.8 mk II

I was given a used 50mm 1.8 mk II (something I've been looking for) but there's a problem with it... when it's set to AF mode, it can't focus properly. When it tries to focus, it just goes back and forth rapidly and sounds like a cat throwing up a hairball. So I'm stuck with using it in MF mode. Which isn't so bad because it's good practice. But it doesn't feel too smooth when I try to focus; it feels "rusty" when I turn the ring, like it needs to be oiled. There's too much friction and it's a pain to focus. It's bad enough that the focus ring is awkwardly placed. Optically though, the lens is still in great condition. It's just the focusing... completely whacked. Is there any way to fix this? Any home remedies? Any way to oil the gears (if any)? I have a cheap 35-80 kit lens from my old old old Rebel and cheap as it is, the focus ring still turns smoothly. Thanks

You got it new?

SuzyView

someone might have dropped it, I wouldnt suggest taking it apart...even though you did get it free, if it still works in MF ten youre a bit ahead of the game. You can see how much it would cost to get it fixed, its a basically cheap lens so if its more than 30 bucks to get it fixed, use it in MF till you can get the 80 bucks to buy a new one.
-zacker-

I'm not sure how old the lens is... and yes, maybe someone dropped it. It came with an old Canon EF-M and I think it was the original lens that came with it. Considering that they stopped making EF-Ms over 10 years ago, the lens may be the same age too. I think one day if I get too frustrated, I'll just take it apart. If that doesn't work out well... I'll just buy a new one. At least it's not a $500+ lens...

oh, if its that old it might be the much sought after 50mm f 2.4? or f1.8? ( i can never remember which is which!) anyway, does it have a metal mount or plastic?
-zacker-

Unfortunately, it's the plastic mount... and it even says MK II on the front.

Canon lenses aren't desgned to be serviced by the consumer, well, no lens really is. If it's very old and hasn't been well treated, there could be any number of problems, including jammed or misaligned gearing from fall, or dried out lubricant. But, it was given to you, so you're out nothing if you can't get it fixed. If the image quality is good, and it's simply a matter of using it in MF mode, I'd say don't look a gift horse in the mouth and use it until you can replace it with a new one or the 50 f1.4.

Mark

That lens doesn't really have the type of bearing surfaces inside that can dry up enough to make the ring hard to turn. I supect that the Autofocus gears are not fully dissengaging, or maybe are damaged.
If you want to take it apart there are some images and instructions here-

https://photography-on-the.net …806&highlight=r​on+chappel

I have a similar but opposite problem, i.e. I can only use auti focus on mine and can't switch to manual. I've read that focus issues are common with this lens because of the cheap consrtuction. I plan to use mine until I can find a good deal on a 50 1.4