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08-24-2015, 10:27 AM   #1
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Takumar 135mm f2.5 lens is stuck on my K5-II

Temporarily my Takumar 135mm f2.5 was stuck on my K5-IIs. No mater how much twisting I did the lens would not come off the camera ! The problem with this scenario is that there is nothing you can do to remove the "original" Pentax M42 Adapter. So your only option is to take the lens apart or send the camera in for repairs. Lucky for me I began to play with the Auto/Manual switch and somehow I was able to remove the lens but that was a scary experience. Does anybody have any experiences like this one ? Right now I'm hesitant to attach the same lens to the camera !

08-24-2015, 10:58 AM   #2
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Was the aperture stuck open or closed when this happened? If you freed it using the auto/man switch, maybe something to do with the aperture pin? (Broken? Sticking out too far?) The third party adapters can be mighty difficult to get off the camera if you leave the spring in (the genuine Pentax less so), but never had a problem unscrewing a lens itself. (Are you sure it is a real Pentax adapter?)
08-24-2015, 11:04 AM   #3
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This is the first I've heard of a jam with the original OEM m42 adapter. With the knock offs it is suspected that the auto/manual release pin is the culprit. This pin is flush on the lens mount about 95 from the aperture stop-down pin. It is suspected that this pin gets caught in the cut outs on the adapter when trying to unscrew the lens. Looking at my original adapters as I screw on the adapter about half of the pin is still covered by the adapter in the cut outs. On the knock-offs the cut is deeper so the pin is not covered allowing it to pop-up in the cut out. With luck a thin enough feeler gauge can be inserted to keep this pin depressed over the cut out and the lens can then unscrew.

You may want to try screwing the adapter on to the lens without mounting it in the camera first to see if this is going on.
08-24-2015, 11:14 AM   #4
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QuoteOriginally posted by Not a Number Quote
This is the first I've heard of a jam with the original OEM m42 adapter. With the knock offs it is suspected that the auto/manual release pin is the culprit. This pin is flush on the lens mount about 95 from the aperture stop-down pin. It is suspected that this pin gets caught in the cut outs on the adapter when trying to unscrew the lens. Looking at my original adapters as I screw on the adapter about half of the pin is still covered by the adapter in the cut outs. On the knock-offs the cut is deeper so the pin is not covered allowing it to pop-up in the cut out. With luck a thin enough feeler gauge can be inserted to keep this pin depressed over the cut out and the lens can then unscrew.

You may want to try screwing the adapter on to the lens without mounting it in the camera first to see if this is going on.



I took a good look at what is going with the lens off the camera. From what I can tell the small pin on the lens that controls the Auto/Manual switch is sticking to one of the cut-out grooves of the adapter. I took a small screw-driver and pressed the small pin all the way into the body of the lens and was able to turn the adapter. Also when I pressed the small pin all the way into the body I was able to move the switch back and forth from Auto to Manual with no problems, so there is nothing wrong with the lens . It could be that my Adapter is not really an original even though it says Pentax on it ? It could also be that it is damaged.


**MODERATOR THERE SEEMS TO BE A DUPLICATE OF THIS THREAD.

08-24-2015, 11:26 AM   #5
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Depending on the vintage the originals say either "ASAHI PENTAX" or "PENTAX" near the clip and at 180 either "JAPAN" or "PHILIPPINES".

Unfortunately the review only shows one side of the "real" adapter.

Pentax Mount Adapter K (M42 Adapter) reviews - Pentax Camera Accessory Review Database

There are photos posted elsewhere but I'd have to find them or the links.
08-24-2015, 11:18 PM   #6
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Wondered why the other thread was closed.

We both thought the little pin was probably a in issue in this.
08-25-2015, 07:29 AM   #7
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QuoteOriginally posted by tim60 Quote
Wondered why the other thread was closed.

We both thought the little pin was probably a in issue in this.

Apparently this only happens with SMC Takumar lenses, because Super Takumar lenses do not have that extra little pin. I wonder if there is a way to disable that extra little pin so that it always remains in the lens body instead of popping out ?
08-25-2015, 07:34 AM   #8
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I've used plenty of Taks with the (extra) little pin with no trouble. I would guess there is actually something wrong with your lens, or it isn't really a genuine Pentax adapter if you are having trouble. The real adapter has been around for decades and was designed to work with these Takumars, so if it isn't then something is broken or malformed or not the real McCoy.

08-25-2015, 07:54 AM   #9
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QuoteOriginally posted by vonBaloney Quote
I've used plenty of Taks with the (extra) little pin with no trouble. I would guess there is actually something wrong with your lens, or it isn't really a genuine Pentax adapter if you are having trouble. The real adapter has been around for decades and was designed to work with these Takumars, so if it isn't then something is broken or malformed or not the real McCoy.
it could be the Adapter is not the real McCoy, if I remember correctly I purchased it "Used", but the seller listed it as "Original" . It has the "Pentax" Logo on the top next to the cut-out and the "Japan" logo at the bottom. Like others have said, it seems that the cut-out is a little different from the "Original" in that the cut-out seems to cut a little deeper ? On the other hand it could also be the lens. The lens is in almost Mint condition except for scuff marks on the Auto/Manual switch where the paint seems to have peeled off, or scraped off. I even touched it up with a Sharpie magic marker because it seemed odd.


The problem with these adapters is that the only way to remove them from the camera is to push on the flimsy clip in the cut out section. There is no way to get to the cut-out and the clip unless you unscrew the lens. With my lens once you start unscrewing it there is the possibility that the little extra pin might pop out of the body and get stuck on the cut-out section of the adapter. So far with the lens and adapter off the camera I have only seen the little extra pin pop out when the switch is set to Auto. However I'm not really sure ? I hate to take a chance and stick that lens back on the camera.

Last edited by hjoseph7; 08-25-2015 at 08:09 AM.
08-25-2015, 08:08 AM   #10
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With the third-party adapters, the first thing you do is remove the little spring clip so they can't get stuck. If you post a pic of the adapter we can probably tell you if it is real.

The tiny little pin (not the aperture pin) is pressed in simply by being mounted. When it is off the camera (and has no rear cap on), the auto-man switch will not work (that's what that pin is -- a little lock for the auto-man switch). So if you can move the switch back and forth, that tells you the pin is being pressed in.
08-25-2015, 08:31 AM   #11
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This is what should happen when the adapter comes in contact with that pin. The cutouts shouldn't be deep enough to let the pin drop into the gap. You should be able to screw the adapter on the lens with the pin sticking out (Auto/Man switch in Auto) and the pin is simply pushed into the lens.



That tiny pin is unfortunately buried deep in the lens. If you have another reason to take the lens apart, like an aperture ring that's hard to move, you could remove it then. It should stay retracted with the Auto/Man switch in Man, if it's working right. I always remove the locking spring on the M42 adapters, which makes them get stuck in the first place.
08-25-2015, 08:35 AM   #12
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These are not the best pictures in the world but here they are:
Attached Images
     
08-25-2015, 08:39 AM   #13
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A noticeable difference between the genuine Pentax adapter and third-party is that the real ones are a bit loosey-goosey in the mount -- if you remove the spring they will probably fall out rather easily. Whereas third-party ones tend to be very snug. Generally you use the real ones with the spring intact as a camera adapter to turn your K-mount body temporarily into an m42 body, and the third-party ones with the spring removed as lens adapters that stay on the lens semi-permanently. (Some people use loctite to keep them on the lens)

---------- Post added 08-25-15 at 11:45 AM ----------

QuoteOriginally posted by hjoseph7 Quote
These are not the best pictures in the world but here they are:
That looks like the real deal. It's a mystery.
08-25-2015, 09:25 AM   #14
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I took a real close look with the lens and adapter off the camera, this time spinning the lens on itself until the 2 cut-outs on the adapter cross over the little extra pin on the lens.


With the switch set to Manual everything seems to work OK. The little extra pin is deep inside the body and the 2 cut outs on the adapter just pass over with no resistance whatsoever.


With the switch set to Auto cut out #1 passes over the little extra pin during the first pass and pushes it slightly inside the body but not all the way. Then cut out #2 with the clip passes over the little extra pin (which is pushed down but not all the way into the body as when the switch is set to Manual), but there is still enough clearance between the pin and the cut out so they do not get stuck ?


I'm thinking that for some reason, or maybe for some defect, when the switch is set to Auto, cut out #1 pushes the little extra pin into the body during the first pass, but then the pin manages to pop out enough to the point that when cut out #2 with the clip passes over it, there is not enough clearance between the adapter and the pin and they get stuck. This means that it's probably the lens not the adapter.
08-25-2015, 09:34 AM   #15
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Appears to be the real thing. It looks to me (compared to my copies) that the remaining part of the ring at the cut-outs is thinner - i.e. the cut-outs are deeper. It could have slipped through QC. Or maybe it is within the specified tolerance but when combined with the one lens the placement is out of spec.

You might be able to glue a shim in there to make the wall thicker at those points. I would use a heavy duty epoxy like the slow cure JB Weld so you wouldn't have to worry about the shims falling off into the camera.

QuoteOriginally posted by hjoseph7 Quote
I'm thinking that for some reason, or maybe for some defect, when the switch is set to Auto, cut out #1 pushes the little extra pin into the body during the first pass, but then the pin manages to pop out enough to the point that when cut out #2 with the clip passes over it, there is not enough clearance between the adapter and the pin and they get stuck. This means that it's probably the lens not the adapter.
Yeah, could be the lens. If you can compare it to another lens maybe you can see what is going on for sure.
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