[Na Horuk]

Ugh, just now as I was walking near my home my camera strap got caught and yanked my K-r out of my hand. The fall wasn't big and the camera appears to be fine. But I had a Pentax-M 50mm f1.7 mounted on it (love that lens!) and now its focus ring will not budge! The aperture ring works (and aperture closes, though the blades make a bit of a rattling, clacking sound now). I've also noticed some dirt specks inside the lens I never noticed before (small, black).
Has this happened to anyone? I would really like to repair the lens myself, rather then buy a new one. I don't think there is a good repair center near where I live (Central Europe). The focusing ring will not move at all. Should I try just pushing the lens to dislodge it? Because the lens appears to be fine, there is no dent or anything on it. Before this fall the lens focusing ring was perfectly smooth. And now its completely jammed at 8ft, won't budge at all in either direction, but I am afraid of applying too much force on it - don't want to damage it further.
This was my fav. lens at the moment

[MysteryOnion]

The fall wasn't big and the camera appears to be fine. But I had a Pentax-M 50mm f1.7 mounted on it (love that lens!) and now its focus ring will not budge! The aperture ring works (and aperture closes, though the blades make a bit of a rattling, clacking sound now).

Is the focus ring "deformed" or not exactly round? It is likely that the lens needs to be taken apart and the focus ring as will as the helicoid need to be inspected.

Depending on how it landed will give you an idea of how bad. If the trauma is high enough, it may cause some cracking of the edges of elements and that is noticeable as black shiny specks or otherwise some paint loss.

[ChooseAName]

If all else fails, I have an M 50/1.7 up for sale in the marketplace but non-US buyers would pay the actual shipping amount.

[ChrisTrevino]

It's always scary dropping camera stuff. I dropped my Super Takumar 50mm f/1.4 on the concrete at the zoo. The focusing ring was bent from the impact.

Luckily for me though the Super Tak is built like a tank, I just took a pair of channel locks to it to re-round the focusing ring.

I definitely would not use the same method of repair on an M / A lens though.

[Na Horuk]

The lens from the outside looks fine, everything is round as it should be. From the outside, I couldn't tell that it fell at all. I am stunned that such a small drop (from less than waist high) could cause so much damage to a metal manual lens.
Yes, if this one is beyond repair I will have to buy another, but the problem is that the second-hand market where I live is really undeveloped and I don't want to buy a lens where a third of what I pay goes just for shipping. Before I decide to buy I will need some time, though, to try and fix this one, take it to a store or two, see if they can do anything.

[hcarvalhoalves]

The lens from the outside looks fine, everything is round as it should be. From the outside, I couldn't tell that it fell at all. I am stunned that such a small drop (from less than waist high) could cause so much damage to a metal manual lens.

That's why - although being dubbed "cheap" - the industry prefers plastic. Not only it's lighter, but on impact it deforms and goes back to it's original form, while metal simply bends.

You can try disassembling and checking if any small parts or debris fell into the helicoid and are jamming it, but if it got bent, I would say it's beyond repair.

[altopiet]

Have a look at this, Pentax 50mm repair 1. it seems this bloke fixed a similar problem.