[ftpaddict]

You have to use the ring on EVERY film SLR except the *ist.

In that case my ZX-30 may be faulty. It only works when the aperture is set to the "A" position.

[MrApollinax]

ftpaddict, according to this:

The Pentax Camera Lens Compatibility Chart

You ZX-30 should have the same mount as the *ist, "Crippled KAF". The description on the page of this mount leads me to believe that on the ZX-30 you need to have the aperature set to "A" since there isn't a contact on the mount to tell the camera what stop you are set to on the aperature ring. Am I reading this wrong? I have been using that chart to figure out what works/doesn't work with my camera when I go lurking around ebay and craigslist.

[ftpaddict]

ftpaddict, according to this:

The Pentax Camera Lens Compatibility Chart

You ZX-30 should have the same mount as the *ist, "Crippled KAF". The description on the page of this mount leads me to believe that on the ZX-30 you need to have the aperature set to "A" since there isn't a contact on the mount to tell the camera what stop you are set to on the aperature ring. Am I reading this wrong? I have been using that chart to figure out what works/doesn't work with my camera when I go lurking around ebay and craigslist.

Thanks for the info. I was just being ironic.

I merely wanted to prove that you didn't really need to use the aperture ring at all times.

[Tuner571]

Is it just the aperture ring that gets stuck? If it's left in A, does the actual aperture work smoothly?
Brian

Yes, its the actual ring thats gets stuck. When left in A mode the camera seems to change it just fine.

[Chr1st0ph3r]

Someone, please stick to the question, what do you do if your aperture gets stuck at f/11. Is there a fix one can apply personally or is it off to Pentax and a hefty bill? Please I have the issue and need it rectified asap. Thank you.

[Just1MoreDave]

Someone, please stick to the question, what do you do if your aperture gets stuck at f/11. Is there a fix one can apply personally or is it off to Pentax and a hefty bill? Please I have the issue and need it rectified asap. Thank you.

I just posted a reply telling someone not to remove the mount on a Pentax-A lens, but now here is a repair that involved removing the mount. I have seen this documented with photos but unless you can find these, all I can tell you is from memory.

Start with a well-lighted workspace, possibly even a large box with a white interior, and a decent screwdriver that fits the screws on the lens mount. A Phillips 00 usually works for me. A fat handle will give you more torque; most cheap "jeweler's screwdrivers" sets have thin handles. With reasonable care, the screws can be removed, you just don't want to strip them.

Be careful when removing the last screw, it's a tricky point. Don't hold the lens by the aperture ring. Don't let the mount just fall off, because there may be some loose bits inside. (The box idea is to catch the parts that fall off.) When you lift off the mount, I think there might be a small brass spring that makes contact with the lens mount and the lens internals. If you see it, it's important to maintain A function, so just keep it and put it back in the same place when you reinstall the mount.

Next, you have to remove the aperture ring without losing other important bits. One important part is a small ball bearing that makes the lens click at every stop. It's pinched between the aperture ring and lens body, and a spring presses it outward against the aperture ring. When you slide the aperture ring off, the brearing (which you can't see until this point) sometimes pops right out. I think it's located near the button that marks the lens release button on the camera, but I'm not sure. Again, just keep track of the bearing for reinstallation.

The next important parts are the broken parts keeping your lens at f11. They are two metal tabs that press out against the aperture ring. They are pointed in opposite directions. On other Pentax lenses, one end is secured to the lens body with a small screw. On the A50/1.7, it's not really secured with a "plastic weld". The weld doesn't last, and when it breaks, the spring tab jams the aperture ring. Hopefully nothing else is broken by attempts to free the aperture ring. If you have some tiny screws, you can use them to secure the spring tabs and probably fix the lens forever. You can redo the plastic welds with a soldering iron but their life expectancy is not great.

Reassembly involves getting the aperture ring back on over the tabs and bearing. Make sure the button to put the lens in A position is still there. The aperture ring only goes on one way and is keyed to the lens's internal workings. It can be tricky and is another time when the bearing can get lost. A very small amount of lithium grease can help the aperture ring turn smoother. Then put the brass spring back and attach the mount.

I don't think I left out anything important. Maybe someone has done this more recently and can check my work.

[tomwil]

I have seen this documented with photos but unless you can find these, all I can tell you is from memory.

Pentax 50mm lens fix

[Tuner571]

Wow, thats a great write-up; I wish that was posted when I asked this question before. Thanks for posting that tomwill!

[deejjjaaaa]

Wow, thats a great write-up; I wish that was posted when I asked this question before. Thanks for posting that tomwill!

in addition

Pentax SMC A5017 Lens Assembly