[magkelly]

Okay, a while back I got an SMC Pentax-A 50 1:1.7 with a bunch of other manual lenses and a P3. Great lens, nice and sharp, love it. I used the 50 on my *ist mostly but after a while I started noticing that the aperture ring would stick and not go above F11 so I put it away for a while. Started using my M42 50/55 a bit more.

Then I found out why it was sticking via another thread on this site and a web link (http://homepage.mac.com/jpelling/50mm/1.7fix.html) and went "OH, so that's it!" I then disassembled the lens as directed, fixed the little metal flange and got the lens working again at all apertures, no problem. I've now got back F16, F22, all's well.

However, and here's my real question here, there's little black screw that goes on the lens ring near the "A" that just plain refuses to stay screwed in no matter what I do. I'm guessing it has something to do with the "A" on the thing? Screw looks stripped maybe? I'm honestly not quite sure I understand what that "A" on this particular lens is for since neither DSLR camera never recognized it as anything but a fully manual lens anyway. There doesn't seem to be any auto mode going on with this lens no matter what is written on it, never has been. Since it's not affecting what I do I was wondering if I just leave this screw out is that okay? It just means I always have to manually focus the lens which is what I was basically doing anyhow, right? I'm not short circuiting the ability of the lens to do anything else?

Just checking before I consign it to a marked baggie put somewhere safe...

Thanks!

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Last edited by magkelly; 06-27-2011 at 12:53 PM.

[Blue]

On the A series lens, when the little button is pushed to lock the aperture ring in the A setting on the aperture ring. This feature was introduced to support the A series bodies that have program modes i.e. PogramSuper, Program A, P3, P30 etc. and all subsequent bodies including our dSLR. If your body wasn't able to recognize it in that A position, something wasn't working correctly.

[magkelly]

I get that but what I am asking is do I need it for manual focusing at all? That feature is just completely disabled from what I can tell. It's basically been acting like an old non-A fully manual lens, I think. Suits me just fine, for a 50 prime, that's no problem, but I'm wondering if I should even bother hanging onto the screw. I think it's useless anyway and I doubt I'd ever sell it being as I had to fix it to even use it. But on the off chance I ever give it to someone, would they even want it?

[Blue]

I get that but what I am asking is do I need it for manual focusing at all? That feature is just completely disabled from what I can tell. It's basically been acting like an old non-A fully manual lens, I think. Suits me just fine, for a 50 prime, that's no problem, but I'm wondering if I should even bother hanging onto the screw. I think it's useless anyway and I doubt I'd ever sell it being as I had to fix it to even use it. But on the off chance I ever give it to someone, would they even want it?

It isn't required for focusing. If everything else is fine, you can use the lens like and M (or k) series with the green button. You just won't be able to set it to A and operate in Aperture priority controlling the aperture from the body.

[magkelly]

That's what I thought but not being to up on the mechanics of old lenses I thought I'd better check. Thanks!

[Just1MoreDave]

Maybe someone replaced the little button to shift it into A with a screw? The only visible screws should be on the mount - 5 to hold the mount on, maybe 3 or so really small ones for the light shield.

An article on the repair is here: https://www.pentaxforums.com/forums/maintenance-repair-articles/88051-pentax-...ng-repair.html The lens sounds like it's working OK as it is, but I would much rather have one stuck as an A lens than stuck as an M lens.

[newarts]

Maybe someone replaced the little button to shift it into A with a screw? The only visible screws should be on the mount - 5 to hold the mount on, maybe 3 or so really small ones for the light shield.

An article on the repair is here: https://www.pentaxforums.com/forums/maintenance-repair-articles/88051-pentax-...ng-repair.html The lens sounds like it's working OK as it is, but I would much rather have one stuck as an A lens than stuck as an M lens.

I agree. Better A than not.

I'd press in on a blunt rod in the hole while trying to witch to the A position.

[magkelly]

I don't know. All I can see is a hole where there apparently was a black plastic screw. I'll give it a shot tomorrow and see I guess. I'm up to my elbows cleaning for unexpected company that's coming. No time to play with my cameras as yet today. Too busy cleaning, darn it! This was so NOT how I planned on spending the rest of my week cleaning, playing tour guide. It sucks. I'd much rather be playing with my K-x.