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05-17-2012, 08:21 PM   #1
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Vivitar p/k lens not mounting on K-5

folks,
I have a Vivitar mc 70-210 f/4.5 p/k bayonet mount lens, which will not mount on my k-5, nor k-10. It looks cock-eyed when you match it up to the camera body, but won't even begin to turn. The mount doesn't look damaged at all. I'm baffled. Can anyone point me in the right direction? I have next to it a pentax-m 50mm which works completely fine.

05-17-2012, 08:33 PM   #2
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Look at the bases of the Viv and the M50. Notice anything? I'll bet the aperture linkage shield on the Viv is much larger than on the M50. (That's the arc of metal beside the aperture flag.) See those little screws holding the shield onto the Viv base? Unscrew them. Remove the shield. Put the shield and screws in a safe place, in case you ever want to sell it as 'mint'; or toss them if you want to keep the lens forever. You should be good to go now. Have fun!
05-17-2012, 08:50 PM   #3
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You are a genius. Done and done. I'll fire off a few tomorrow and see if it's worth anything to me. Can you explain why this step is necessary, or when it became a compatibility problem with newer camera bodies? Thanks regardless. -Adam
05-17-2012, 09:01 PM   #4
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I just removed that plate from my Vivitar (Kobori #77xxxx) 28-105 f/3.5-4.5. It appears to be intended to protect the aperture lever when it's on - but as noted it won't mount on the digital bodies. Images from mine looks pretty nice but seems to overexpose by most of 1EV; I'll need to check for sticky blades, just in case. If exposure is right on when shot wide open but gets progressively brighter as I stop down.. well that would suggest it's not stopping down!

05-17-2012, 09:08 PM   #5
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QuoteOriginally posted by weave2d2 Quote
Can you explain why this step is necessary, or when it became a compatibility problem with newer camera bodies?
Several third party lens manufacturers made lens for k-mount that worked just fine on early k-mount cameras but have issues on newer cameras, Vivitar in particular. Pentax modified the camera specs to accommodate the power zoom contacts, (which are now used as the SDM contacts). The modification did not conflict with any lens that Pentax had made but it did conflict with some of the third party lenses. Whether Vivitar did not follow the specifications for k-mount precisely or whether there was no specification for the aperture shield I do not know. It seems odd they would make the shield bigger than what Pentax was using but perhaps they had a reason.

Anyway, those lenses need modified to work on newer cameras.
05-17-2012, 09:12 PM   #6
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No genius, I just remember a few things. Vivitar (Poore & Best Distributing) used to market Pentax-compatable SLRs built to accept that larger shield. I dunno why, just that they did. [EDIT: Jatrax just came up with the 'why'.] Some of what I remember includes:
Any PK lens will fit on any PK body. BUT some very few Vivitar and other lenses have the large aperture-link shield, so the lens won't mount on modern dSLRs. And some very few Ricoh and compatable lenses have the infamous "Ricoh pin" which can get stuck in a (d)SLR's AF-screw hole. Both the shield and the pin are easily removed.
Other than that, I sometimes remember to... wait, I forgot what it was I was going to remember. Oh bother.
05-18-2012, 12:09 AM   #7
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I'd recommend cutting the shield down and re-attaching it to protect the aperture lever and prevent dust from getting into the lens. If you ever want to sell it you can then do so as "ready for digital".
05-18-2012, 12:35 AM   #8
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and old Sigma PK

QuoteOriginally posted by RioRico Quote
No genius, I just remember a few things. Vivitar (Poore & Best Distributing) used to market Pentax-compatable SLRs built to accept that larger shield. I dunno why, just that they did. [EDIT: Jatrax just came up with the 'why'.] Some of what I remember includes:
Any PK lens will fit on any PK body. BUT some very few Vivitar and other lenses have the large aperture-link shield, so the lens won't mount on modern dSLRs. And some very few Ricoh and compatable lenses have the infamous "Ricoh pin" which can get stuck in a (d)SLR's AF-screw hole. Both the shield and the pin are easily removed.
Other than that, I sometimes remember to... wait, I forgot what it was I was going to remember. Oh bother.
and I used to have a Sigma Zoom Master ( the older one with PK mount, not the newer one with PKA ) , the aperture link was just too long , had to trimm ~2mm,
it was fine on all film bodies but would not mount on KX.
Now I have Vivitar S1 70-210 3.5 ( Kiron/Kino) waiting for P/K mount operation

05-18-2012, 08:18 AM   #9
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I need to get my Dremel tool out of storage.
05-18-2012, 09:13 AM   #10
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QuoteOriginally posted by weave2d2 Quote
I need to get my Dremel tool out of storage.
Yes, with a Dremel you can easily modify Nikon, Olympus OM, Yashica C/Y, and other lens mounts, to fit on PK cameras. The first mod is always a nerve-wracking experience. The next chops take 5 minutes each, including setup and cleanup. Beware: lens-chopping becomes addictive.
05-23-2012, 05:46 PM   #11
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I first hit this problem with a Tokina SZX60-300 when I bought my Z-1 (as jatrax mentions - although I don't agree Pentax changed the specs as all previous Pentax lenses weren't affected). Pentax's official line was always that third party accessories may damage the camera (and void the warranty), so I guess there wasn't a spec and Pentax were free to do what they wanted.

Incidentally the power zoom functionality still works (at least on my K-5 & FA 28-80 f/3.5-4.7), although without the specific zoom modes the Z-1 had.
05-23-2012, 10:49 PM   #12
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QuoteOriginally posted by johnha Quote
(as jatrax mentions - although I don't agree Pentax changed the specs as all previous Pentax lenses weren't affected)
All I meant was that they added the powerzoom contacts, thus changing something in the camera, the change did not affect any Pentax lens. Whether they did it deliberately to cause issues with third party lenses, never bothered to check about third party lenses, or had to build it that way and thus inadvertently messed up third party lenses is unknown.

Had Vivitar and others followed the specification (or copied exactly the Pentax flange if there was no spec) there would have been no issue. Today, I would assume that Pentax would cooperate closely with third parties making lenses for k-mount especially in providing them with exact specifications and tolerances. I am not sure that was done as much back then.
05-24-2012, 12:01 AM   #13
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Given that there was absolutely no practical reason for the extra long flange, I can't see Pentax bothering to check on and accomodate weird third party mount versions.
05-24-2012, 12:22 AM   #14
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QuoteOriginally posted by Jonathan Mac Quote
Given that there was absolutely no practical reason for the extra long flange, I can't see Pentax bothering to check on and accomodate weird third party mount versions.
Especially for lenses that match Pentax offerings. The aforementioned 60-300 doesn't -- but other wide-flange lenses were direct competitors. It's for the 3rd-party makers to build lenses that match the cameras, not vice-versa.
05-24-2012, 02:24 AM   #15
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QuoteOriginally posted by weave2d2 Quote
I need to get my Dremel tool out of storage.
Whatever the cause for these large flanges, here's what the problem (probably) looks like:



Obviously, a Dremel tool is just fine, but for me a primitive hack-saw did the job:



Uder all circumstaces: Do dismantle the flange from the lens first.
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