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05-16-2015, 07:03 PM   #1
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Can't mount old lenses to my K3

Hey guys. Since i got my K3 ş had this problem of not being able to mount certain lenses on my K3, i didn't wanted to play around it too much but it is bugging me off now.

All of the lenses i own mounts and works fine with K5ii yet doesn't mount on k3.

Ricoh 50mm f2
M42 lens adapter
Kiron 28mm f2

Simply does not fit in. Any suggestions ?

05-16-2015, 07:13 PM   #2
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I have a Chinon lens which I can't use on my DSLRs due to a metal flange which needs to be removed. That can't be the case with your lenses if they were on the K5ii. Hopefully someone who has one of those specific lenses can suggest a reason?
05-16-2015, 07:26 PM   #3
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I always though my K5ii might be little bit dented or there might be a problem with my m42 adapter. But since i have multiple lenses right now it kind of odd.

Update: It mounts if i really force it in but i get hard time removing the lens, with all 3
05-16-2015, 07:57 PM   #4
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Are you trying to mount the lens to the adapter first, then mount it on the camera.
with some cameras that will not work.
the way it's supposed to work is, the adapter goes on the camera first. Then install the lens.
Hope this helps.

05-16-2015, 08:31 PM   #5
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QuoteOriginally posted by G.E.Zekai Quote
All of the lenses i own mounts and works fine with K5ii yet doesn't mount on k3.
The mounts are the same on the two cameras. The only issues might be clearance for the flash housing.

QuoteOriginally posted by promacjoe Quote
Are you trying to mount the lens to the adapter first, then mount it on the camera.
with some cameras that will not work.
the way it's supposed to work is, the adapter goes on the camera first. Then install the lens.
Hope this helps.
Can you give an example/explanation? I have a nice selection of M42 lenses and routinely mount adapter to lens first and have done so for many years on multiple film and digital K-mount bodies. I find it easier to thread that way.*


Steve

* The instructions with the genuine adapters and various Pentax bodies over the years have suggested either one way or the other. In practice, they potentially differ in only one respect, that being the rate of "decent" of the lens onto the mount face. I am assuming that the bayonet ears have a different pitch than the M42 thread (1mm).
05-16-2015, 08:41 PM   #6
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QuoteOriginally posted by G.E.Zekai Quote
Update: It mounts if i really force it in but i get hard time removing the lens, with all 3
Non-Pentax brand adapter? That is fairly typical. The genuine Pentax adapter fits loose in the mount while 3rd-party adapters do not. I have a couple of K-mount lenses that are fairly tight in the mount. One is a Rikenon-P 50/2 and the other is a Vivitar 28/2.8 CF (Komine). They have a tight fit on all of my K-mount bodies including my Ricohs.

With adapted lenses, I have found it useful to depress the lens lock button for the mount when attaching/removing the lenses. Many of my M42 lenses have screw holes and such on the lens flange that tend to catch on the retaining pin and AF drive pawl. Pressing the button retracts both.


Steve

Last edited by stevebrot; 05-16-2015 at 10:22 PM.
05-16-2015, 09:10 PM   #7
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It is a non pentax adapter that's why i though the problem might be in adapter. Yet Kiron 28 and Ricoh 50 are K mount and have no problem at K5ii but extremely stiff at K3
05-16-2015, 09:15 PM   #8
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QuoteOriginally posted by G.E.Zekai Quote
All of the lenses i own mounts and works fine with K5ii yet doesn't mount on k3.

Ricoh 50mm f2
M42 lens adapter
Kiron 28mm f2

Simply does not fit in. Any suggestions ?
I have mounted every one of those on my k3. I did notice though they were a bit tighter at first....not anymore.

05-16-2015, 10:36 PM   #9
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the reason I say you need to put the adapter on the camera first, is that some K Mounts allow the adapter to set a little deeper than others. And since the mating surface on many screw mount lenses is flat, you may have a hard time mounting your lens if you do it the other way around. Most of my lenses work fine Leaving the adapter on the lens, but I Have had a couple that will not work like that, On certain cameras it works fine but on others it will not work. All it takes is a few hundredths of an inch difference.
05-17-2015, 12:53 AM   #10
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The K and M series camera manuals instruct you to screw the adapter on to the lens first. The LX manual doesn't mention the adapter at all. The "A" series manuals when they have instructions for the adapter say to mount it in the body first. The later manuals if they mention the adapter at all just talk about compatibility.

The current instruction sheet, the Hoya era and "A" era sheets say to put the adapter in the camera first. I can't find a copy of the instruction sheet from the K and M series era (Asahi Pentax branded). They may tell you to mount the ring on the lens first as the camera manuals do.

When I'm not using screw mount lenses the adapter is screwed on to my most used M42 lens. It's more convenient that way than having to dig around in my camera bag to find it.. I have yet to have a problem.

After all if the adapter is sticking out further than the camera mount then the rear lens mount would not be flush and not tighten down. At most the adapter will be flush with the camera mount and that would not be a problem because the rear mount would be flush too. Besides you can always back it off a touch and the adapter will adjust into the mount since it is locked.
05-17-2015, 03:10 AM   #11
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It's not an adapter problem as it also happens with K-mount lenses. So can we stay on subject

As mentioned earlier, a matter of tolerance. It might be that the mount on the K3 is out of spec by a fraction of a millimeter. Assuming all Pentax lenses that you have do fit properly, I van't really advise on a way forward.

My approach would be to let it loosen over time mounting and unmounting lenses that fit followed by the 'tighter' ones. Alternative can be a warranty check to see if the mount is within spec.
05-18-2015, 12:07 AM   #12
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QuoteOriginally posted by promacjoe Quote
the reason I say you need to put the adapter on the camera first, is that some K Mounts allow the adapter to set a little deeper than others.
No...any mount that does that is not a K-mount. Not that it makes much difference. Think about how the mount works and the fact that the position of the adapted lens is determined by the mating of the lens flange to the body flange. When properly engaged, the adapter does nothing but provide tension to hold the lens against the body. If the adapter protrudes past the body mount face, it is poorly made. Both my genuine Pentax adapters sit flush in the mounts of all eight K-mount bodies I have used in the past couple of years. They are also loose in the mount such that the lens secures by snugging up against the mount face.

If your adapter has inadequate lead in with its tangs to engage the body when mounted to the lens, there is something seriously wrong with the adapter.


Steve

Last edited by stevebrot; 05-18-2015 at 12:20 AM.
05-18-2015, 12:08 AM   #13
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QuoteOriginally posted by Not a Number Quote
I can't find a copy of the instruction sheet from the K and M series era (Asahi Pentax branded). They may tell you to mount the ring on the lens first as the camera manuals do.
I have a copy and it does. I will have to find it though.


Steve
05-18-2015, 11:31 AM   #14
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QuoteOriginally posted by stevebrot Quote
No...any mount that does that is not a K-mount. Not that it makes much difference. Think about how the mount works and the fact that the position of the adapted lens is determined by the mating of the lens flange to the body flange. When properly engaged, the adapter does nothing but provide tension to hold the lens against the body. If the adapter protrudes past the body mount face, it is poorly made. Both my genuine Pentax adapters sit flush in the mounts of all eight K-mount bodies I have used in the past couple of years. They are also loose in the mount such that the lens secures by snugging up against the mount face.

If your adapter has inadequate lead in with its tangs to engage the body when mounted to the lens, there is something seriously wrong with the adapter.


Steve
No, you have it backwards.The adapter does not protrude out, it is recessed in, pulling the lens against the K mount prematurely making it tight. it's all about tolerance. A few thousands discrepancy on the mount + a few thousands discrepancy on the adapter can make a big difference. If it was as you say protruding out, there would be no real friction to hold the lens in place. just the spring behind the K mount. And by the way I only have original Pentax adapters. purchased in the late 70s/80s from authorized Pentax dealers in the area where I live. they are "Genuine Pentax M42 to K Mount adapters".

Foot note: Before the digital age, there were dozens of camera stores in my area. The last one is scheduled to close at the end of this month. This store was family owned, and has been passed down through the generations, A sad legacy of the digital economy.
05-18-2015, 01:34 PM   #15
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QuoteOriginally posted by promacjoe Quote
it is recessed in, pulling the lens against the K mount prematurely making it tight.
All I can say is, "not my experience", though I won't say it is impossible.


Steve
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