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02-21-2011, 11:19 PM   #16
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great video. yes, all the genuine Pentax M42 adapters I own have some play like that such that the lenses with narrow base will wobble.
I got lucky with a batch of $7 Chinese M42 adapters that fit snug into the camera mount and do not wobble, not one bit.

here's a thread i had posted:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/101836-helios-...-solution.html

unfortunately, after i got a few of these "good ones", a second batch i ordered from the same dealer were obviously a different make and were not as good...oh well.

i still recommend taking a chance on a few of the cheap adapters, some are very bad, and some are actually superior to the Pentax, at least when it comes to a snug fit for those Russian lenses.

good luck

02-22-2011, 12:37 AM   #17
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The genuine Pentax adapter is designed to NOT snug up against the mount by the tangs alone. It is supposed to turn without resistance in the mount. Bend the tangs too much and good luck getting it off. Unfortunately, this feature can be a problem with some lenses that have a narrow base. My Jupiter-9 (M42) rocks ever so slightly. My other M42 lenses including the Helios 44M work just fine. There are a few reports on PF where the play was fairly alarming.

I can imagine that small diameter lenses such as M39 LTM could be a real problem when double-adapted.


Steve
02-22-2011, 05:12 AM   #18
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QuoteOriginally posted by stevebrot Quote
The genuine Pentax adapter is designed to NOT snug up against the mount by the tangs alone. It is supposed to turn without resistance in the mount....
Perhaps, but I believe the lens side of the K mount (or the adapter) is designed for the ears to "snug up" when the lens base contacts the flat surface of the mount (otherwise wide base Pentax lenses would wiggle too.) Now we are faced with a situation where there is no flat surface on the lens to snug up to the camera mount.

QuoteQuote:
Bend the tangs too much and good luck getting it off. ...
Certainly that's true. That's why I recommended gradually decreasing the ear-flange gap of the ear's trailing edge until things are tight enough. I've done it a couple times; never unsuccessfully.

Dave
02-22-2011, 08:02 AM   #19
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QuoteOriginally posted by newarts Quote
Perhaps, but I believe the lens side of the K mount (or the adapter) is designed for the ears to "snug up" when the lens base contacts the flat surface of the mount (otherwise wide base Pentax lenses would wiggle too.) Now we are faced with a situation where there is no flat surface on the lens to snug up to the camera mount.



Certainly that's true. That's why I recommended gradually decreasing the ear-flange gap of the ear's trailing edge until things are tight enough. I've done it a couple times; never unsuccessfully.

Dave
The adapter should "snug up" with a lens attached and be relatively loose with the lens removed. At least that is my experience with other than the Jupiter-9. A little judicious adjustment probably won't hurt, but the important thing is to proceed with caution.


Steve

02-22-2011, 09:22 AM   #20
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the looseness of the pentax adapter is obviously a non-issue for most lenses that have a wide base. This thread however is specific to those narrow base lenses and how to keep them from wobbling.
02-22-2011, 04:53 PM   #21
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Tried pounding on the adapter a little, and it's snug when first inserting it in the mount, but then it wobbles anyway. I don't want to go any further with the hammer since I want the adapter to come off again

Now to decide on an infinity or flanged adapter...but I need to re-cap the power section of my home theater receiver soon
09-16-2013, 02:43 AM   #22
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QuoteOriginally posted by ryan s Quote
When the lens doesn't contact the lens mount of the camera, the lens rotates about a millimeter laterally whenever I touch it. Searched the interwebs, searched here, and couldn't find any topics that pertained to this particular issue.

Is there a remedy to this? Bending the spring on the adapter further outwards after squaring off the nearest flange on the lens mount looks to be the only way
Hey Ryan you probably solved your problem, but I just want to confirm that the loose adapter issue is still happening. I just bought a Helios 44-2 and it is indeed loose exactly like your video, but another M42 lens is stable and is indeed due to larger flange size.

In addition, the lens flange on my 44-2 is loose too, so the "overall looseness" is a combination of lens flange and adapter, for me. I'm able to live with that so no problem.
09-18-2013, 12:36 PM   #23
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I have the exact same problem with my own Mir 1B lens even though it has a native M42 mount. The lens body is only slightly larger than the M42 mounting threads and the lens never snugs up against the camera's own lens mounting surface. My infinity focus point occurs well before the end of the focus ring. Can I assume that a flange which may push the lens out a bit may still work to keep infinity focus?

One other thing too in my case: my genuine M42 adapter has a slightly shallower profile than the camera's lens mounting surface. Meaning, the surface of the M42 adapter sinks below the surface of the camera lens mounting surface. I was thinking I could use this bit of depth to accommodate a flange.

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