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02-06-2016, 04:06 PM   #1
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Loose lens Mounts- Old K Mount Lenses

Hi, New here and just introduced myself over at the introduction section.

I have recently purchased two Pentax k mount lenses. I was thrilled to find them at a second hand store for not much money. I bought an adapter for my Canon T4I which had an auto confirm chip which caused a lens error message so I just removed the chip and use it without the focus confirm. It was only 9 bucks so the adapter itself was worth that.

My problem, which does not seem to affect the image, is hat the mount on both lenses is loose. It appears to move in all directions when the barrel of the lens is pushed away from center. I have attached pics. The red arrow indicates where the movement is occurring. All other areas of the lens seem nice and tight. These areas however are loose to the point they rattle a little bit.

I am capable of removing parts and getting them back together and ordering replacement parts if necessary. Currently the lenses are usable and I did not want to tear into them and make them not usable. Especially if they are normally like that.

Any advice on how to correct the looseness or advice about an auto-confirm chip compatible with the T4I would be appreciated. Thanks!

~Jeff

2.8-22 lens is 90mm Panagor PMC Auto Macro 62mm No 825218

2.5-32 lens is 105mm Vivitar series 1 VMC Macro Telephoto No 22403042

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02-06-2016, 04:17 PM   #2
osv
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the arrows look like they are pointing to the aperture ring, in both cases? is that what's loose?

are the rings so loose that they are changing the aperture by themselves, or ?

if you are talking about the barrel moving around, it's probably an adapter issue.
02-06-2016, 04:27 PM   #3
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QuoteOriginally posted by osv Quote
the arrows look like they are pointing to the aperture ring, in both cases? is that what's loose?

are the rings so loose that they are changing the aperture by themselves, or ?

if you are talking about the barrel moving around, it's probably an adapter issue.
Yes, the lens moves right where it exits the aperture ring. I didn't use the best description possible by saying lens mount..... Thanks for your reply!

---------- Post added 02-06-16 at 04:34 PM ----------

QuoteOriginally posted by jeff456 Quote
Yes, the lens moves right where it exits the aperture ring. I didn't use the best description possible by saying lens mount..... Thanks for your reply!
I edited my reply to include more information but Its not showing up.

The adapter fits great and is nice and tight. The movement is occurring from side to side and up and down. It feels as if there should be a bushing or something like that between the barrel and the aperture ring to fill the space between the two. Maybe a worn part or something,...
02-06-2016, 04:38 PM - 1 Like   #4
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I have the Kiron version of the Vivitar 105/2.5 in your first shot. On the Kiron I can remove four crosspoint screws in the ring above your arrow, the one with the red dot. One is visible in your shot above and left of the A. Then you can slide everything from mount to that ring off the rest of the lens. There are two long stamped-metal arms that control the aperture, maybe 2.5 inches long, that will come with this piece. That's where your loose part is. I have taken this piece off and can't see anywhere that might even come loose, though.

I've also owned the Panagor and never had any looseness. I never had a reason to take that one apart. Both these lenses were built by Kiron. It looks like the screws are all JIS. You'll probably want JIS screwdrivers.

02-06-2016, 04:52 PM   #5
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Video of Movement

Hopefully you can see the movement in this video. It comes from the entire aperture not just the silver selector ring.

Thanks!

Jeff

---------- Post added 02-06-16 at 04:55 PM ----------

QuoteOriginally posted by Just1MoreDave Quote
I have the Kiron version of the Vivitar 105/2.5 in your first shot. On the Kiron I can remove four crosspoint screws in the ring above your arrow, the one with the red dot. One is visible in your shot above and left of the A. Then you can slide everything from mount to that ring off the rest of the lens. There are two long stamped-metal arms that control the aperture, maybe 2.5 inches long, that will come with this piece. That's where your loose part is. I have taken this piece off and can't see anywhere that might even come loose, though.

I've also owned the Panagor and never had any looseness. I never had a reason to take that one apart. Both these lenses were built by Kiron. It looks like the screws are all JIS. You'll probably want JIS screwdrivers.
Thank you!

---------- Post added 02-06-16 at 05:32 PM ----------

Hopefully you can see the movement in this video. It comes from the entire aperture not just the silver selector ring.

Thanks!

Jeff

---------- Post added 02-06-16 at 04:55 PM ----------
02-07-2016, 08:20 AM   #6
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I think I know what you're describing, I have the same thing on my Makinon 135mm lens, which is a manual K mount around 40 years old.

The entire front section of the lens would wobble in any direction when I first started using it. It didn't seem to affect pictures, just made me worried.

In the bottom picture, the 2.8 to 22 lens, over to the left of the 22 is a small screw. It should have 3 or 4 going around the lens at that point. Those were loose. I went through mine and partially disassembled it, tightening everything I could reach, and put it back together. Those screws and the ones on the bottom of the K mount, facing the camera, were more loose than anything else. It didn't completely stopo it, but it did minimize the wobble in the lens, I have very little now and it still works fine. And it went from a lens I didn't like and rarely used to one of my favorite ones. Probably 80% of the pictures I've taken in the past 2 years have been using that lens.

If it were me I'd try to take it apart at least partially and tighten everything in sight, then put it back together. Be careful to use a screwdriver that fits well and do not over tighten. Having done it, those tiny screws are a bear to remove and replace if the heads break off or strip...( I worked in the tool room of a machine shop for 2 years, had to deal with screws 1 or 2 sizes larger lots of times, that's probably the biggest screw anywhere in a lens. Not fun...)

Don't use loktite, if you want to use anything like that, use fingernail polish. It will hold screws in place but is easy to break loose when necessary.
02-07-2016, 10:52 AM   #7
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QuoteOriginally posted by Paleo Pete Quote
I think I know what you're describing, I have the same thing on my Makinon 135mm lens, which is a manual K mount around 40 years old.

The entire front section of the lens would wobble in any direction when I first started using it. It didn't seem to affect pictures, just made me worried.

In the bottom picture, the 2.8 to 22 lens, over to the left of the 22 is a small screw. It should have 3 or 4 going around the lens at that point. Those were loose. I went through mine and partially disassembled it, tightening everything I could reach, and put it back together. Those screws and the ones on the bottom of the K mount, facing the camera, were more loose than anything else. It didn't completely stopo it, but it did minimize the wobble in the lens, I have very little now and it still works fine. And it went from a lens I didn't like and rarely used to one of my favorite ones. Probably 80% of the pictures I've taken in the past 2 years have been using that lens.

If it were me I'd try to take it apart at least partially and tighten everything in sight, then put it back together. Be careful to use a screwdriver that fits well and do not over tighten. Having done it, those tiny screws are a bear to remove and replace if the heads break off or strip...( I worked in the tool room of a machine shop for 2 years, had to deal with screws 1 or 2 sizes larger lots of times, that's probably the biggest screw anywhere in a lens. Not fun...)

Don't use loktite, if you want to use anything like that, use fingernail polish. It will hold screws in place but is easy to break loose when necessary.
Thanks for replying. I did go ahead and try to disassemble the mount and aperture area by removing all the screws I could find. After removing them I still could not budge anything to get it to come off. Tried twisting and pulling but no luck. Just went ahead and reassembled the screws and is now much tighter than it was. It's acceptable, and doesn't affect pictures so I'm just leaving it alone.

A comment about you being a machinist. I worked as a welder in a repair/fabrication shop. Anything and everything came through there. I used to build railings for beach resorts and a 1/4 inch over a long run was fully within tolerance. Had a machinist friend who made the molds for injection molding process. They were accurate down to the hundred thousandths of an inch. We used to laugh about the scale of the things we worked on. .
02-11-2016, 12:31 PM - 1 Like   #8
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I know what you mean. I did a bit of TIG welding too, a lot of other stuff. As a result of the first shop I worked in, repairing cutting tools for lathe and milling machine, I had to know TIG, sandblasting, brazing, lathe, milling machine, tool grinding, drill and end mill sharpening, do my own QC, and more while most people just run a lathe or mill. Interesting stuff. Then I got into carpenter work and the uncle I worked with gave me fits because I didn't like leaving anything 1/8 inch off...I've been working with .0005" - .001" tolerances for years...I can turn my truck around in 1/4 inch...OK not really but it seems like it by comparison. A 1/8" difference is like a football field compared to machinist tolerances.

For those of you who don't understand this, look at the cellophane on a cigarette pack. That's .001" thick. I used it a lot to get my starting point for cutting parts, touch that cellophane and the cutter is .001" off the part. That's how much room I had for mistakes. Get it .002" too big or too small and it's scrap, and I just cost the shop several hundred dollars...I scrapped one part that was $8000 finished...boss was not happy, I almost got fired...not my fault though, my dial indicator went bad and I didn't know it. The pointer needle came loose from the spindle and would not point to the same spot every time.

Keeping up with tools in the tool room was a headache, some of the small insert clamp screws are as small as #2, and some of the people running the machines would clamp them down so tight they sometimes would break trying to loosen them, or strip out the heads....then I had to try and remove and replace the leftovers...I learned to be really picky about worn out screwdrivers and Torx wrenches...always use a good screwdriver that fits the screw.

02-11-2016, 12:58 PM - 1 Like   #9
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A foot-wide plank can shrink or grow by 1/4" in width over seasons, easy - and that's a stable, dry piece. It'll keep doing that forever, as long as humidity changes. If it can't expand or shrink, it will crack or break something else.
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