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07-25-2017, 01:19 PM   #1
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Trouble mounting SMC Takumars (M42) onto K-mount camera bodies

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Hi all - hoping someone can talk me down from the ledge here. I'm very frustrated with a problem I've encountered in mounting a couple of M42 SMC Takumar lenses (4/50 macro, 2.5/135), via adapter ring, onto a few different K-mount cameras (ME Super, K10D, K-5II). Basically, I cannot seem to screw these lenses in far enough to "set" into the adapter, and when they are screwed as tight as I am comfortable, the aperture ring cannot be moved because I believe there is an aperture level protruding from the rear of the lens that is butting up against the inside of the camera body.

Troubleshooting:
Used two different (2nd party) adapter rings - no good
Used K-mount film and digital SLRs - no good
Used pre-SMC takumars in the same bodies - these lenses fit in and work just fine. They don't have aperture levers.
Used M42 mount bodies - the lenses in question work perfectly in them

So - am I missing something obvious I should be doing, or can I really not use these beautiful lenses on my k-mount bodies?

Please help!

07-25-2017, 02:40 PM   #2
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QuoteOriginally posted by boydmain Quote
Used two different (2nd party) adapter rings
Use a Pentax M42 adapter
07-25-2017, 02:48 PM   #3
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QuoteOriginally posted by pschlute Quote
Use a Pentax M42 adapter
Thanks for the response. I've looked at those and I can't understand mechanistically how that would make a difference. If the problem I'm having is caused by a aperture lever protruding from the rear of the lens, an adapter of equivalent dimension, sitting at an equivalent position relative to the camera body, would presumably yield an equivalent physical incompatability....

Now, if the dimensions of the generic adapter are slightly too small in the depth dimension, then perhaps that could cause the problem.
07-25-2017, 03:22 PM   #4
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QuoteOriginally posted by boydmain Quote
Used two different (2nd party) adapter rings - no good
Agree with @pschlute , I have always used the original adapter and no problem. A fair price would be 40 euros/dollars but if you are patient enough you can get one at a lower price.

07-25-2017, 03:55 PM - 1 Like   #5
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QuoteOriginally posted by boydmain Quote
Basically, I cannot seem to screw these lenses in far enough to "set" into the adapter, and when they are screwed as tight as I am comfortable, the aperture ring cannot be moved because I believe there is an aperture level protruding from the rear of the lens that is butting up against the inside of the camera body.

Troubleshooting:
Used two different (2nd party) adapter rings - no good
Used K-mount film and digital SLRs - no good
Used pre-SMC takumars in the same bodies - these lenses fit in and work just fine. They don't have aperture levers.
Used M42 mount bodies - the lenses in question work perfectly in them

So - am I missing something obvious I should be doing, or can I really not use these beautiful lenses on my k-mount bodies?

Please help!
YES they do work well on all K mount bodies

I have never come across a problem with the aperture pin butting up against anything in any Pentax K mount camera body when using a M42 adapter so I don't think that is anything to do with your problem.

Lets start with the basics of using a M42 adapter to cover all bases.

Lens:
Do not fit adapter to the lens.
On any lens that has the Auto/Manual switch for aperture it must be set to the Manual setting. Look through lens & confirm aperture opens/closes when you move aperture ring. If aperture is opening/closing, that's all there is for setting the lens & it is ready for use with M42 adapter.

M42 adapter:
Being a aftermarket adapter should not cause any problems as the distance lens is set back into camera body is determined by the base (flange) of the M42 mount & not the adapter. The main problem with aftermarket adapters is usually the screw to attach the locking spring being too long causing problems when removing the adapter or just generally poor fit of the K mount bayonet. Neither of these issues will cause the problems you are having.

The correct way to use the adapter (either genuine Pentax or Chinese aftermarket flangeless) is to mount the adapter into the camera body first, turn & latch into place.

Now screw the lens into the camera/adapter combo. No need to go overboard with tightening lens onto camera. Just nip it up firm, try turning the focusing ring both directions & if lens does not try to unscrew from the mount that's all you need. DO NOT try to tighten lens to make aperture/focus distance scale line up at the top. It is common (especially on after market) for the scale to not line up correctly with top of camera body. It's just a minor inconsistency you learn to deal with as you get used to using it.

Now try turning the aperture ring while looking at the front of the lens & you should see it opening & closing.

You should be good to go shooting!

Some users unscrew/remove the lock spring from the adapter to overcome the adapter removal problem with aftermarket adapters, but I am not a fan of this idea as you are relying totally on friction to keep the lens attached to camera body. It is just as easy to fix the real problem (file down or replace screw) & use the adapter as it was originally designed to be used with 100% security of lens being attached. I have never had a problem with a aftermarket adapter being used as it was designed for once it has been repaired/fitted properly.

Last edited by Tool_Horder; 07-25-2017 at 04:02 PM.
07-25-2017, 11:28 PM   #6
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QuoteOriginally posted by boydmain Quote
Hi all - hoping someone can talk me down from the ledge here. I'm very frustrated with a problem I've encountered in mounting a couple of M42 SMC Takumar lenses (4/50 macro, 2.5/135), via adapter ring, onto a few different K-mount cameras (ME Super, K10D, K-5II). Basically, I cannot seem to screw these lenses in far enough to "set" into the adapter, and when they are screwed as tight as I am comfortable, the aperture ring cannot be moved because I believe there is an aperture level protruding from the rear of the lens that is butting up against the inside of the camera body.

Troubleshooting:
Used two different (2nd party) adapter rings - no good
Used K-mount film and digital SLRs - no good
Used pre-SMC takumars in the same bodies - these lenses fit in and work just fine. They don't have aperture levers.
Used M42 mount bodies - the lenses in question work perfectly in them

So - am I missing something obvious I should be doing, or can I really not use these beautiful lenses on my k-mount bodies?

Please help!
Here are the rules for S-M-C and and SMC Takumar lenses as far as the Auto/Manual switch and aperture ring function:
  • There is a very small interlock pin just a little wide of the mount threads. If this pin is not depressed, the Auto/Manual switch cannot be moved to the manual position. Attempts to force the mechanism may cause it to jam, perhaps with permanent damage to the lens and impaired aperture ring movement*. Note that this is not the larger silver aperture actuator pin that is positioned just inboard of the mount threads.
  • Attaching the rear cap or a proper adapter will depress the small pin allowing free movement of the Auto/Manual switch. The same may be accomplished by mounting the lens to most Pentax M42 bodies (those not supporting open aperture metering).
  • The aperture ring should be fully functional regardless of whether the pin is depressed or the position of the Auto/Manual switch
Now regarding the information you supplied:
  • There is nothing that protrudes from the SMC/S-M-C lenses that will bind or interfere with anything inside a K-mount SLR or will bind the aperture ring. (I am typing this with an S-M-C 28/3.5 in hand along with a genuine Pentax adapter, a Ricoh K-mount film camera and my K-3 for reference.)
  • Are you sure your adapters are M42 (Praktica/Pentax) to Pentax-K and not something else? A proper adapter (both flanged and non-flanged types) will screw fully onto the lens until tight against the rear flange and should depress the small interlock pin. Items such as a T-mount (42mm diameter, but with a different thread pitch) will bind and not thread on properly.
  • To check your adapter(s), attach them to the lens to confirm that they screw fully on to the lens (do not force). If there is any binding, take the adapter off and don't attempt again. When fully screwed on, the small pin should be depressed, the Auto/Manual switch should be free to move both directions, and the aperture ring should rotate easily to its full range both directions. Note that some inexpensive adapters may have an overly-long screw securing the retention spring. This long screw may jam into the lens threads such that full attachment is not possible.
I suspect that your adapters are not proper.

I don't know what you mean by "no aperture levers".



Steve

* I have personally never jammed an SMC lens, but have read that a total jam up is possible.

Last edited by stevebrot; 07-26-2017 at 12:08 AM. Reason: Decided to not go there...
07-25-2017, 11:47 PM   #7
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QuoteOriginally posted by stevebrot Quote
I suspect that your adapters are not proper.
Here are some examples:

Genuine Pentax Mount Adapter K




Third-party Non-flanged Adapter (not recommended without modification)




Third-party Flanged Adapter (no infinity focus)




T-2 K-mount Adapter: Will Not Work! Wrong Thread Pitch!




I hope this helps.


Steve


Last edited by stevebrot; 07-26-2017 at 12:10 AM.
07-26-2017, 12:46 AM   #8
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take a snapshot of your adapter, we might help further, it's difficult to imagine the cause without a photo of your M42 adapter
07-26-2017, 01:18 AM - 1 Like   #9
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Some third party adapters have a ring at the end that goes into the camera to press in the aperture stop down pin. These do not fit properly on later Takumar lenses that have the aperture control linkage on them. These adapters work best on lenses without a Auto/Manual switch. These adapters negate the function of the Auto/Manual switch and the lens will always stop down regardless of the switch setting.

Do not use these style adapters on the late model Takumar lenses with the aperture control linkage.

B&H sells such an adapter.


General Brand Pentax-K Body to Universal Lens Adapter ABPKS B&H

Below is the mount of a Super-Multi-Coated Takumar with the aperture control linkage. Note the square tab at 9 o'clock and the control linkage from 3:15 o'clock to about 6 o'clock:
Attached Images
View Picture EXIF
PENTAX K10D  Photo 

Last edited by Not a Number; 07-26-2017 at 10:06 AM.
07-26-2017, 02:26 PM   #10
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QuoteOriginally posted by Not a Number Quote
Some third party adapters have a ring at the end that goes into the camera to press in the aperture stop down pin.

That's a new one. I have not seen that style of adapter with the inner flange for stop down pin.

Looking at the design of the Kipon adapter it looks like it could be the cause of the problem as the aperture lever would be rubbing against the inner flange. This would result in all the symptoms boydmain is seeing from his trouble shooting.
07-26-2017, 04:56 PM   #11
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QuoteOriginally posted by Not a Number Quote
Some third party adapters have a ring at the end that goes into the camera to press in the aperture stop down pin. These do not fit properly on later Takumar lenses that have the aperture control linkage on them. These adapters work best on lenses without a Auto/Manual switch. These adapters negate the function of the Auto/Manual switch and the lens will always stop down regardless of the switch setting.

Do not use these style adapters on the late model Takumar lenses with the aperture control linkage.

B&H sells such an adapter.
Wow! Just when one starts thinking that they have things down pat, another wrinkle in the adapted lens compatibility story pops up. Except for photos, I have never seen a Kipon adapter, though I have been aware of their existence and utility when used with lenses lacking the A/M switch. It never occurred to me that the aperture coupler and boss on the back of an SMC lens might be fouled with such a unit. Good work!

BTW, I noticed that the B&H listing is for "General" brand and that the user reviews appear to be referencing several different adapter variants. I wonder it the Kipon is what they are really offering. If so, $16 is not a bad price. I have seen Kipon in a price range similar to the genuine Pentax. Adorama asks $45 for one. I also noticed that a disturbing number of the user reviews mentioned stuck adapters or damage to their cameras.


Steve
07-26-2017, 08:42 PM   #12
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I had a Kipon adapter and it doesn't work with my Takurma 50mm 1.4 because of the ring at the end! but it works well with the Helios 58mm so it's glued to my Helios now ^^
07-26-2017, 09:04 PM   #13
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QuoteOriginally posted by stevebrot Quote
BTW, I noticed that the B&H listing is for "General" brand and that the user reviews appear to be referencing several different adapter variants. I wonder it the Kipon is what they are really offering. If so, $16 is not a bad price. I have seen Kipon in a price range similar to the genuine Pentax. Adorama asks $45 for one.
I've seen inner flange adapters for a lot less than the Kippon...from a seller in Lithuania...

FLANGED M42 LENS TO PENTAX K MOUNT ADAPTER TO INFINITY BRAND NEW (1 pcs.) | eBay

I've seen genuine adapters available for the same price. (An Asahi for $24.50 for example). But nothing is as ridiculous as the $89 B&H wants for one...

And I think "General Brand" from B&H just means "cheapest we can find"...
07-26-2017, 09:30 PM   #14
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QuoteOriginally posted by boriscleto Quote
I've seen inner flange adapters for a lot less than the Kippon...from a seller in Lithuania...

FLANGED M42 LENS TO PENTAX K MOUNT ADAPTER TO INFINITY BRAND NEW (1 pcs.) | eBay
That as got to be one of the roughest M42 adapters I have ever seen.

QuoteOriginally posted by boriscleto Quote
And I think "General Brand" from B&H just means "cheapest we can find"...
The thought occurred to me too.


Steve
07-26-2017, 09:39 PM - 1 Like   #15
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The Kipon adapter you have is ideal for pressing the pin of "auto" lenses that lacks an A/M switch (i.e. later iterations of Helios 44Ms, the Zenitar M2S). However I have confirmed that it will interfere with the open-aperture lever on SMC Takumars. I personally use a Lomo-made adapter. It lacks the flange, making it work perfectly with SMC Takumars, and it can be removed easily without the help of the key, just like a genuine Pentax adapter.

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