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03-14-2016, 09:05 AM   #1
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Are parts interchangeable among 50mm Pentax lenses (different max apertures)?

Hi,

I have a couple of 50mm f/1.4 M42 Pentax lenses. One of them is missing the front bezel/ring, and I was wondering can I use the bezel ring, and I think maybe the piece that goes under the bezel ring, from, say, a 50mm f/2.0 lens on the f/1.4 lens?

Thanks,
Jim

03-14-2016, 09:27 AM   #2
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QuoteOriginally posted by ohaya Quote
Hi,

I have a couple of 50mm f/1.4 M42 Pentax lenses. One of them is missing the front bezel/ring, and I was wondering can I use the bezel ring, and I think maybe the piece that goes under the bezel ring, from, say, a 50mm f/2.0 lens on the f/1.4 lens?

Thanks,
Jim
Likely not. The diameter of a f/1.4 lens is probably wider than an f/2 lens.
03-14-2016, 09:38 AM   #3
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Sometimes parts aren't even interchangeable between two lenses with the exact same name and age. Different lenses are really unlikely.
03-14-2016, 10:41 AM   #4
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QuoteOriginally posted by enoeske Quote
Likely not. The diameter of a f/1.4 lens is probably wider than an f/2 lens.
Darn! Reality strikes (I should've realized what you said !!). The thing is, for the price of buying a used 50mm f1.4, even for parts one, that's almost the same as a good working one ...

Ok, going off on a tangent then: I actually have 2 50mm f/1.4 lenses: The bezel is missing from one of them and the other is complete, but the focus ring has a ding in it. Both seem to work fine, so would you all cannibalize one of them for parts to make one good/complete one or just leave both alone?

03-14-2016, 02:32 PM   #5
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QuoteOriginally posted by ohaya Quote
Hi,

I have a couple of 50mm f/1.4 M42 Pentax lenses. One of them is missing the front bezel/ring, and I was wondering can I use the bezel ring, and I think maybe the piece that goes under the bezel ring, from, say, a 50mm f/2.0 lens on the f/1.4 lens?

Thanks,
Jim


Jim,

Is the bezel the top ring with the lens name and numbers written on it? If so, that ring from my M 50 f2 screws right onto my S-M-C Takumar 50 f1.4 with no problem.
(In this picture I've swapped rings on the two lenses. The M 50 is on the right.)






As for what's underneath the top ring, I don't have much experience working on lenses. But, the Tak and M look a lot different from each other.







Tim

Last edited by .a.t.; 03-14-2016 at 04:54 PM. Reason: details, details...
03-14-2016, 06:50 PM   #6
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QuoteOriginally posted by .a.t. Quote
Jim,

Is the bezel the top ring with the lens name and numbers written on it? If so, that ring from my M 50 f2 screws right onto my S-M-C Takumar 50 f1.4 with no problem.
(In this picture I've swapped rings on the two lenses. The M 50 is on the right.)






As for what's underneath the top ring, I don't have much experience working on lenses. But, the Tak and M look a lot different from each other.







Tim


How did you get the bezel ring off? I've been working at it this evening, with a set of filter wrenches, but it won't budge !!

Also, I noticed that even though I think both lenses are f/1.4, they look different from each other similar to the two you had in your first pic. The knurling style looks completely differently exactly like the two lenses you showed.

Did they have different "styles" of the 50mm f1.4 that looked that differently?

EDIT: Also, I think the lens that I have that is missing the bezel ring is also missing something else. This page:

http://retinarescue.com/pentax50mmf1.4.html

refers to a "filter mount ring" underneath the bezel ring,. but mine doesn't seem to have that:


Last edited by ohaya; 03-14-2016 at 07:01 PM.
03-15-2016, 02:02 AM   #7
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QuoteOriginally posted by ohaya Quote
How did you get the bezel ring off? I've been working at it this evening, with a set of filter wrenches, but it won't budge !!
Maybe you're trying to remove the filter mount ring rather than just the name ring (bezel)? The name ring spins down into the filter mount ring and should come loose when some friction is applied. In my case, both name rings on my lenses weren't very tight and I was able to get them off just by putting one finger into a rubber glove and turning them.
The filter mount ring is held in place by screws which can be reached after the name ring is removed.

QuoteQuote:
EDIT: Also, I think the lens that I have that is missing the bezel ring is also missing something else. This page:
Pentax 50mm f/1.4 strip-down instructions
refers to a "filter mount ring" underneath the bezel ring,. but mine doesn't seem to have that:
Right, in this picture of my Takumar you can see the filter mount ring at the top. But, I don't know if filter mount rings from different generations of Takumar / Pentax 50s are interchangeable.





QuoteQuote:
Also, I noticed that even though I think both lenses are f/1.4, they look different from each other similar to the two you had in your first pic. The knurling style looks completely differently exactly like the two lenses you showed.

Did they have different "styles" of the 50mm f1.4 that looked that differently?
Yes. "Super Takumar" and "Super-Multi-Coated Takumar" lenses had metal focus grips while "SMC Takumar" lenses had rubber focus grips. You can read more about them in the lens database here:
SMC/S-M-C/Super Takumar 50mm F1.4 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database

03-15-2016, 03:53 AM   #8
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QuoteOriginally posted by .a.t. Quote
Maybe you're trying to remove the filter mount ring rather than just the name ring (bezel)? The name ring spins down into the filter mount ring and should come loose when some friction is applied. In my case, both name rings on my lenses weren't very tight and I was able to get them off just by putting one finger into a rubber glove and turning them.
The filter mount ring is held in place by screws which can be reached after the name ring is removed.

Right, in this picture of my Takumar you can see the filter mount ring at the top. But, I don't know if filter mount rings from different generations of Takumar / Pentax 50s are interchangeable.





Yes. "Super Takumar" and "Super-Multi-Coated Takumar" lenses had metal focus grips while "SMC Takumar" lenses had rubber focus grips. You can read more about them in the lens database here:
SMC/S-M-C/Super Takumar 50mm F1.4 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database

Hi,

Perfect! I got the name ring and filter mount ring off! Your comment about sticking finger to turn the ring made me realize, like you said, that I was trying to turn the "outer" filter mount ring instead of just the name ring at the front. So I took some rubber pad I had and pushed on the name ring and turned it.

That exposed the 3 screws underneath, that hold the filter mount ring. I unscrewed those, and was able to get the filter mount ring out.

FYI, I was able to move both the filter mount ring and the name ring to the other (I guess) Super-Multil-coated takumar. I'm guessing that the filter mount rings are the same among the 50mm lenses?

Anyway, for now I have a complete 50mm f/1.4, although the name plate is wrong, and I have to keep an eye out for a "for parts".
03-15-2016, 11:22 AM   #9
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QuoteOriginally posted by ohaya Quote
. . .
Anyway, for now I have a complete 50mm f/1.4, although the name plate is wrong, and I have to keep an eye out for a "for parts".

Success! I'm happy to hear it, Jim.
I just love Fast Fifties. I'm going to take one of mine out today for some exercise.


Tim
03-15-2016, 01:30 PM   #10
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QuoteOriginally posted by .a.t. Quote
Success! I'm happy to hear it, Jim.
I just love Fast Fifties. I'm going to take one of mine out today for some exercise.


Tim

Yeah, I know. I *thought* that I had an old f/1.2 at one time, but I can't find it... or I was dreaming !!
03-24-2016, 03:24 PM   #11
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QuoteOriginally posted by .a.t. Quote
Success! I'm happy to hear it, Jim.
I just love Fast Fifties. I'm going to take one of mine out today for some exercise.


Tim

Hi Tim,

I was able to find a "for parts" SMC - M. It should be here in a few days and then I can try it on my lens. It'll still be kind of weird, with the wrong labelling, but at least it'll be "whole" again (hopefully)!

Thanks,
Jim

EDIT: "When it rains, it pours"!! I just found someone who had an old/non-working SLR + an actual Takumar f1.4, so I put in a low-ball offer and they accepted it. So now I will have the correct name ring too. When/if I get this lens back completely together, it's definitely going to be a "Franken-lens", and I'll have some junk parts that I won't know what to do with.

Last edited by ohaya; 03-24-2016 at 07:42 PM.
03-24-2016, 08:28 PM   #12
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QuoteOriginally posted by ohaya Quote
Hi Tim,

I was able to find a "for parts" SMC - M. It should be here in a few days and then I can try it on my lens. It'll still be kind of weird, with the wrong labelling, but at least it'll be "whole" again (hopefully)!

Thanks,
Jim

EDIT: "When it rains, it pours"!! I just found someone who had an old/non-working SLR + an actual Takumar f1.4, so I put in a low-ball offer and they accepted it. So now I will have the correct name ring too. When/if I get this lens back completely together, it's definitely going to be a "Franken-lens", and I'll have some junk parts that I won't know what to do with.

Wow! Great news, Jim. I guess you've been living right!
And as far as I'm concerned, having too many lenses and spare parts is a good kind of problem to have.


Enjoy your toys,
Tim
03-25-2016, 03:21 PM   #13
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QuoteOriginally posted by .a.t. Quote
Wow! Great news, Jim. I guess you've been living right!
And as far as I'm concerned, having too many lenses and spare parts is a good kind of problem to have.


Enjoy your toys,
Tim
Well the first one (an SMC-M K-mount) arrived today, but I can't get the name ring out... it won't budge. I'm using a jury rigged tool, the cap from a spray bottle plus some tape around the edge, so I ordered a tool (a big rubber stopper) to see if that works. BTW, this uses a 52mm filter, right?

So a 50mm lens ring tool (http://www.amazon.com/Lens-Ring-Tool-42mm-Rubber/dp/B002QI1BTI) will work for it?

Actually now that I have this one, even if I could loosen the name ring, I don't know if it'll come off, as I see that there a small area at the front edge that is dinged. Also, the lens actually looks pretty clean other than the cosmetics, so I may just keep it as a working lens if I can't get it apart.

EDIT: Here's a couple of pics of the dented part of the filter mount ring:



and:



I've been researching what to do about that dented area and was looking at tools to remove it, but then I ran across this thread:

http://photo.net/classic-cameras-forum/00Xhk1

and in particular the post by Clay James, Nov 19, 2010 where he says:

"If you have a section of threads that are flattened (a small section) then you can take a dremel and a small burr and remove the damaged threads, the rest of the threads will hold the filter in place."

I was actually thinking about doing this even before finding that suggestion.

The thing is, if you can see it in the pics above, the way that the ring was dented, the threads in the dented area a "compressed", and, because of that, I think that even if I got one of those vise tools to push the ring outwards again, the threads would still be messed up. I'm thinking that I can carefully grind the inside side of the filter ring mount in that area to get rid of the "bump" in the threads and then a filter ring should thread ok?

Thoughts???

Thanks,
Jim

Last edited by ohaya; 03-25-2016 at 05:03 PM.
03-25-2016, 04:59 PM   #14
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QuoteOriginally posted by ohaya Quote
Well the first one (an SMC-M K-mount) arrived today, but I can't get the name ring out... it won't budge. I'm using a jury rigged tool, the cap from a spray bottle plus some tape around the edge, so I ordered a tool (a big rubber stopper) to see if that works. BTW, this uses a 52mm filter, right?

So a 50mm lens ring tool (http://www.amazon.com/Lens-Ring-Tool-42mm-Rubber/dp/B002QI1BTI) will work for it?

Actually now that I have this one, even if I could loosen the name ring, I don't know if it'll come off, as I see that there a small area at the front edge that is dinged. Also, the lens actually looks pretty clean other than the cosmetics, so I may just keep it as a working lens if I can't get it apart.
If I am not mistaken, all takumar/pentax 50mm f/1.4 are 49mm filter size, you can check for your lens in the lens database.

About the name ring. A small trick that works quite often in these situations. You take a hair drier, apply the heat on the exterior of the barrel that holds the name ring and then, as it expands a bit, you should be able to get the name ring out in no time. Do not overheat, 50 degrees Celsius should do it just fine.
03-25-2016, 05:25 PM   #15
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QuoteOriginally posted by Audi 5 cyl Quote
If I am not mistaken, all takumar/pentax 50mm f/1.4 are 49mm filter size, you can check for your lens in the lens database.

About the name ring. A small trick that works quite often in these situations. You take a hair drier, apply the heat on the exterior of the barrel that holds the name ring and then, as it expands a bit, you should be able to get the name ring out in no time. Do not overheat, 50 degrees Celsius should do it just fine.
I think you're right about the diameter. I have 2 different 50mm f1.4 lenses with M42 mount, and I think both of those are 49mm filter size, or at least the filter mount ring and the name ring appear to be interchangeable.

I also have one K-mount SMC-A 50mm f1.4, the one just came in, and that looks like 52mm filter ring.

The thing that caused confusion for me is that the two M42 lenses look different... the knurling style is different between them but the knurling style of one of the M42 lenses is similar to the SMC-A K-mount.

I do have the 2nd f1.4 lens coming, and that one IS an M42, so hopefully the filter mount will be ok and hopefully I can remove the name ring successfully.

Having said all that, any thoughts about dremeling the inside of the filter mount ring on that SMC-A, to get rid of the "ding"?
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