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09-22-2021, 03:27 PM   #1
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$89 for a T mount ring?

I was thinking about getting a T mount Takumar lens for my Pentax, but it turns out the adapter ring is more expensive than the vintage prime lens I was gonna get?

https://www.bhphotovideo.com/c/product/673977-REG/Pentax_30120_Mount_Adapter...981&


How they justify the price for this piece of aluminum ring? Are there people really paying this much for this thing?

09-22-2021, 03:35 PM   #2
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There is no such thing as a T-mount Takumar. m42 and T-mount are different things (although they both have 42mm threads, the pitch is different). And yes the "genuine" Pentax-branded m42-K adapter (again, not t-mount) you are looking at is pricey, but you can get generic ones for much much less ($15-$20) or a used genuine one for maybe $40-$50
09-22-2021, 04:32 PM   #3
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1) “Pentax Screw Mount” aka m42 and “T-Mount” have different thread pitch and flange focal distance.

2) that price is much higher than I’ve seen in the past. The adapter doesn’t wear out easily so a used one is probably fine.

3) the genuine Pentax model is better than most alternatives. Some old stock of better alternative adapters work fine. I have the real thing and I have a Kalt that was NOS from the 70’s. I have no trouble with either one.
09-22-2021, 08:25 PM - 1 Like   #4
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Check out other "online" sources; you will find the Pentax brand M42 to K adapter from $20 to $100; you will have to be patient to find them in the lower price range- but they are there.

A generic brand will be less, just be sure you get one without a "flange" if you want to achieve infinity focus.

09-23-2021, 12:03 AM   #5
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This adapter has definitely gotten more expensive over the years. That said, it's the only one of exceptional quality and is worth getting if you plan to spend a lot of time using m42 lenses.

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09-23-2021, 08:19 AM   #6
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The Pentax original is still available to order from an authorised UK Pentax retailer for £38 including tax Pentax M42 To K Mount Bayonet Body Mount Adapter - Best Price at Bristol Cameras
I can only imagine that if a UK retailer can source these, so can any other authorised retailer.
The price is high, (though not as high as many third-party retailers would have you believe!), doubtless reflecting the low demand. The quality is faultless. Getting an old lens seemingly permanently jammed on your modern digital camera can be a very high price to pay for a "cheaper" alternative
09-23-2021, 12:04 PM   #7
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I don't see how anyone can get a "permanent" jam by using a screw to K adapter- unless they just will not follow instructions! JMHO.

09-23-2021, 01:06 PM - 1 Like   #8
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If you buy one of the cheaper ones and don't remove the little spring thing, you are guaranteed to lose your mind trying to get a lens unstuck. Otherwise, I prefer the cheaper ones (with the spring removed) as you can just leave them on the lens as an adapter.
09-23-2021, 01:51 PM   #9
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QuoteOriginally posted by DonV Quote
I don't see how anyone can get a "permanent" jam by using a screw to K adapter- unless they just will not follow instructions! JMHO.
That's what I thought, 'till it happened to me
Fortunately it was on an old film body I keep for the testing of these things and a bit of brute force freed it all up, but I'd have been very reticent to treat one of my digital bodies like that!
Ended up having to remove the lens mount from the body (and dropping all the little springs and contacts) so's I could release the offending adaptor from behind … I didn't bother with a "post-mortem" to confirm the hows and whys, I just binned it!
09-23-2021, 02:12 PM   #10
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" release the offending adaptor from behind"

A pre-installation exam would have been helpful and perhaps avoided the problem; but either your adapter was broken/modified or you didn't notice how to release it from the front;
Some of these are designed to lock in place- others are not; but they are not designed to require disassembly to remove.
09-23-2021, 02:22 PM   #11
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Again, if you buy one of the cheaper third-party ones and don't take the spring out immediately before you use it, it doesn't matter one bit how it was "designed", YOU WILL HAVE A LENS GET STUCK. That will happen, guaranteed. (You will have no such problems with a genuine Pentax one though.)
09-23-2021, 03:06 PM   #12
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QuoteOriginally posted by DonV Quote
" release the offending adaptor from behind"

A pre-installation exam would have been helpful and perhaps avoided the problem; but either your adapter was broken/modified or you didn't notice how to release it from the front;
Some of these are designed to lock in place- others are not; but they are not designed to require disassembly to remove.
The adaptor was certainly faulty in one respect or another.
I've had a Pentax original since my *ist film camera, so am well aware of the use and how to release it, I even still have the original instructions which recommend the use of "a ballpoint pen or the like" to release the spring and rotate the adaptor, (I usually manage quite well with a fingernail).
However, the faulty unit jammed onto the lens thread, possibly due to an over-length screw or a deformed thread, and the force required to overcome this jamming caused the spring to distort, preventing release from the front!
Needless to say, I've not used an aftermarket adaptor since without removing the spring first

---------- Post added 09-23-21 at 03:17 PM ----------

QuoteOriginally posted by vonBaloney Quote
Again, if you buy one of the cheaper third-party ones and don't take the spring out immediately before you use it, it doesn't matter one bit how it was "designed", YOU WILL HAVE A LENS GET STUCK. That will happen, guaranteed. (You will have no such problems with a genuine Pentax one though.)
This advice is all very well in this day and age with the benefit of hindsight, but "back in the day" I certainly was unaware of any potential problems, simply acknowledging that the after-market items needed the supplied release tool to remove the adaptor, assuming because that option was cheaper than producing the adaptor to the critical clearances required for ease of removal whilst retaining a shake-free fit.
09-23-2021, 03:26 PM   #13
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QuoteOriginally posted by kypfer Quote

This advice is all very well in this day and age with the benefit of hindsight, but "back in the day" I certainly was unaware of any potential problems, simply acknowledging that the after-market items needed the supplied release tool to remove the adaptor, assuming because that option was cheaper than producing the adaptor to the critical clearances required for ease of removal whilst retaining a shake-free fit.
My post was addressed to the one above mine (sorry should have quoted) in which it seems to be suggested that knowledge of "how it works" will save you. It won't -- only removing the spring will. So just shouting for everyone to hear: NEVER USE A THIRD-PARTY ADAPTER OF THIS TYPE WITHOUT REMOVING THAT SPRING FIRST.
09-23-2021, 03:45 PM   #14
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QuoteOriginally posted by vonBaloney Quote
So just shouting for everyone to hear: NEVER USE A THIRD-PARTY ADAPTER OF THIS TYPE WITHOUT REMOVING THAT SPRING FIRST.
My Kalt has worked perfectly every time. However I like my Pentax better. The Kalt requires a tool to remove and that’s more of a hassle.
09-24-2021, 12:11 PM   #15
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QuoteOriginally posted by DonV Quote
I don't see how anyone can get a "permanent" jam by using a screw to K adapter- unless they just will not follow instructions! JMHO.
'Tis simple. Buy a third-party adapter and use it without modification. As mentioned above, few, if any third-party offerings properly engage with the lock provision of the K-mount and as a result, over-rotate in the K-mount opening with a resulting jam. When it happened to me (generic, sold as Bower), I was luck and able to free the adapter after several hours of fiddling. Other users have resorted to removal of the K-mount and/or use of a Dremel tool with cutting wheel.

As mentioned on a few other threads, Fotodiox has ceased to offer other than flanged-type adapters because this issue with the in-mount type. Other brands apparently have less integrity. Below is a usage guide for third-party adapters that I wrote for a different thread, a few years ago. I do think it is still decent advice and covers the bases.
QuoteQuote:
  • Remove the flat metal spring as a first step before you even think of attaching it to a camera. (Set the spring and screw aside.)
  • Carefully attach the adapter to a lens you might care less for than others, flat side towards the lens flange. If the thread starts to bind, don't attempt to force or work it past a rough spot, remove immediately. Your lens is not intended to act as a tap for cleaning badly cut threads. The adapter should screw on with little resistance and snug up with the adapter's face tight against the lens flange.
  • Remove the adapter from the lens and carefully insert it into the mount throat on the body, taking care to align the red dots.
  • Rotate the adapter into the mount. You should be able to mount it using a finger nail in the index notch and finger pressure alone. Most (all?) brand-x adapters are a tighter fit than the genuine*, but overly tight is not a good thing. The tangs on the camera side may be stainless steel, but they should not be used to shave excess thickness off the plated brass adapter. Any shards released would not be a good thing to have in your shutter or on the sensor. The adapter will not lock in place due to the retention spring being removed. Note that the face of the adapter should be slightly inset below the face of the K-mount flange or at very most, exactly flush with its face. Any protrusion will disallow infinity focus.
  • Carefully screw your lens onto the mounted adapter, taking care to note body clearance for any projections (e.g. the Auto/Manual switch). If there is any contact with the body other than at the lens flange, stop and reverse the lens out of the adapter. That lens will not work with your camera. It should snug up gradually against the camera's mount flange and when firmly mounted, you should not be able to see any part of the bright adapter body through any gaps. If you can, there may be a problem with the lens not having a broad enough lens flange. There are work-around solutions on this site.
  • Work the focus ring and aperture ring. Ideally, the lens should remain firmly in place in the mount despite the retention spring being removed. If not, some other means will have to be used to hold everything in place.

* The genuine should fit fairly loose in the mount opening; third-party offering seldom mount the same as the genuine.

Steve

Last edited by stevebrot; 09-24-2021 at 12:49 PM. Reason: typos
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