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03-25-2016, 05:48 PM   #16
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QuoteOriginally posted by ohaya Quote
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"?
Here are all the m42 takumars. I hope this can help you learn more about your lenses.

For the dremeling part, I would just file the dent on the interior side. Damaging a couple of mms of the thread won't change a thing when it comes to hood or filter installation. I guess it is ok to use a small power tool like dremel for this job.

03-25-2016, 06:34 PM   #17
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QuoteOriginally posted by Audi 5 cyl Quote
Here are all the m42 takumars. I hope this can help you learn more about your lenses.

For the dremeling part, I would just file the dent on the interior side. Damaging a couple of mms of the thread won't change a thing when it comes to hood or filter installation. I guess it is ok to use a small power tool like dremel for this job.
Thanks for the suggestion re. the search. Looks like for the M42, I have one that looks like one of the 1st two and a second one that looks like one of the last two.

For K mount, it looks like the one I have is the first one here:

F1.4 Pentax K Lenses between 49mm and 50mm | PentaxForums.com

I will grind down the "bump" on the inside of the threads, probably dremeling. I need to figure out/make sure that I can keep the shavings/dust away from the lens first though.
03-25-2016, 09:14 PM   #18
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I tried heating up using a hair dryer, but no luck getting the name ring off ... Looking at the lens straight on, it looks like the filter ring mount may be a little out of round, which may be why I can't get the name ring off? So anyway, I'm thinking that I may have to drill a couple of holes in the name ring in order to turn it and get it off. I know that that isn't a good thing, but I think I have to. Anyway, will think about it further tonight unless someone has some other idea.

Jim
03-26-2016, 09:07 AM   #19
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I started working on the rear/mount end. I am following this video:

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/192993-grea...ns-repair.html

I got the retaining ring out and the one lens, but there's still a lens inside (just behind the aperture). Does that one remaining lens STAY inside the body and if you have to clean it, do you have to clean it from the front, i.e., open the blades wide open and then clean from the front?

Or is there a way to get that lens (the one behind the aperture blades) out?

Thanks
Jim

03-26-2016, 10:37 AM   #20
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I just found this thread asking about the same thing (getting to the front lens of the back group).

http://forum.mflenses.com/remove-rear-group-from-super-multi-coated-takumar-...-4-t31333.html

Apparently there's 2 ways:

- clean the front of the lens from the front (i.e., open the shutter wide and clean from the front) or

- remove the 3 screws (around the sides of the lens) and push from the back. Apparently the whole thing (the shutter and the front lens of the back group) come out together.

Of course, the 2nd choice means I have to remove the fron lens, but I still haven't gotten the name ring off yet !!
03-26-2016, 12:22 PM   #21
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I finally got the name ring off:



I had to drill two counter-posing holes and use a spanner wrench, but it was VERY difficult to get out even then. I eventually had to put the spanner into a bench vise and even then I got to the end and it wouldn't budge. I tried heat using a heat gun that I have and then the ring finally started turning again.

Here's the ring:



Here's looking into the front of the lens:



It looks like there is only one screw there (there should be three screws).

Does anyone know where I might purchase screws, or maybe the size of the screws?

Jim
03-26-2016, 12:25 PM   #22
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I have a lot of woodworking tools, so to repair a dented filter ring, I make a half circle wood form for the outside of the filter ring. Then I make a stick, put it inside the filter threads and whack it until the filter section is reasonably round. The stick end doesn't last very long so I file it off and start over. I have a lot of scrap pieces of maple to use. I test with a filter to see if the threads work.

Sometimes the ring will be round enough but the threads will be squashed together and still not work. Then I'd use a dremel or file on the damaged sections. Later on, I'd remove the glass from an old filter and screw the filter into the damaged threads. Then the filter's threads can be used for hoods or filters.

When the name ring won't budge, I make sure the filter threads are really clean with an old toothbrush. Just one piece of sand can make it stick. Sometimes I carefully use WD40 on the threads. I'm not that worried about the WD40 migrating to the aperture blades because if I get the lens apart, I can clean it up before it gets that far. You just don't want WD40 on the name ring because your friction tool won't work. Sometimes I make another wooden stick with an end like a flat screwdriver. I put that end in one of the engraved vertical lines, like the I in ASAHI. Then I can hold the stick at an angle and tap the other end to loosen the name ring. I won't get it moving in one tap but tapping in several places around the ring often works. You might find plastic screwdrivers meant for electronics. A metal screwdriver is bound to slip.

Takumar 50 and 55mm lenses all have 49mm filter threads. Many other Takumars used 49mm filter threads as well, when the front of the lens was small enough. The SMC Pentax lenses, also called the K series, used 52mm filter threads instead. Then for the M and later lenses, Pentax switched back to mostly 49mm, except for a few exceptions. The K-series and A-series 50mm f1.2 lenses both use 52mm filters, and for some reason the DA 50mm f1.8 also does. Your Pentax-A 50mm f1.4 uses 49mm filters - I know the front element looks pretty big but still 49mm.
03-26-2016, 01:31 PM   #23
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QuoteOriginally posted by ohaya Quote
I finally got the name ring off:

It looks like there is only one screw there (there should be three screws).

Does anyone know where I might purchase screws, or maybe the size of the screws?

Jim
I could send you some but it is a long way from France I guess. Tell me if you are interested.
I've occasionally seen large amount of screws selling on ebay, like this for example. Just make sure to compare with one that you have before you buy.

03-26-2016, 02:58 PM   #24
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QuoteOriginally posted by Audi 5 cyl Quote
I could send you some but it is a long way from France I guess. Tell me if you are interested.
I've occasionally seen large amount of screws selling on ebay, like this for example. Just make sure to compare with one that you have before you buy.


Hi,

Actually, I need to correct what I said earlier. When I actually started taking out the filter mount ring, I found TWO screws in there (only one was missing). I went ahead and ordered from the link you had.... probably not bad to have an assortment of spares!!

---------- Post added 03-26-16 at 03:00 PM ----------

QuoteOriginally posted by Just1MoreDave Quote
I have a lot of woodworking tools, so to repair a dented filter ring, I make a half circle wood form for the outside of the filter ring. Then I make a stick, put it inside the filter threads and whack it until the filter section is reasonably round. The stick end doesn't last very long so I file it off and start over. I have a lot of scrap pieces of maple to use. I test with a filter to see if the threads work.

Sometimes the ring will be round enough but the threads will be squashed together and still not work. Then I'd use a dremel or file on the damaged sections. Later on, I'd remove the glass from an old filter and screw the filter into the damaged threads. Then the filter's threads can be used for hoods or filters.

When the name ring won't budge, I make sure the filter threads are really clean with an old toothbrush. Just one piece of sand can make it stick. Sometimes I carefully use WD40 on the threads. I'm not that worried about the WD40 migrating to the aperture blades because if I get the lens apart, I can clean it up before it gets that far. You just don't want WD40 on the name ring because your friction tool won't work. Sometimes I make another wooden stick with an end like a flat screwdriver. I put that end in one of the engraved vertical lines, like the I in ASAHI. Then I can hold the stick at an angle and tap the other end to loosen the name ring. I won't get it moving in one tap but tapping in several places around the ring often works. You might find plastic screwdrivers meant for electronics. A metal screwdriver is bound to slip.

Takumar 50 and 55mm lenses all have 49mm filter threads. Many other Takumars used 49mm filter threads as well, when the front of the lens was small enough. The SMC Pentax lenses, also called the K series, used 52mm filter threads instead. Then for the M and later lenses, Pentax switched back to mostly 49mm, except for a few exceptions. The K-series and A-series 50mm f1.2 lenses both use 52mm filters, and for some reason the DA 50mm f1.8 also does. Your Pentax-A 50mm f1.4 uses 49mm filters - I know the front element looks pretty big but still 49mm.

Unfortunately, I don't have a lot (like almost none) woodworking tools. You know, I've seen suggestions like what you said, and maybe someone should SELL those wooden forms plus the wood tap!

EDIT: Would something like this work?

Wood Forming Block with 5 Wooden Shapers for Shaping Bending Dapping 6pc Set | eBay

---------- Post added 03-26-16 at 03:07 PM ----------

Hi,

BTW, I have completely cleaned and re-assembled the lens (minus the name ring) and it seems to working fine, and the lens is now super clean (to me)!!

I haven't tried to put a filter on the filter ring yet....

EDIT: I tried a 52mm UV filter on the lens, and the filter wouldn't mount, not even close !

Last edited by ohaya; 03-26-2016 at 04:43 PM.
03-27-2016, 08:35 PM   #25
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Hi,

I had some success, sort of.

I made a wooden form using a 2 1/4" hole saw, then I lay the filter ring mount in the form and put the cut out piece inside the filter ring mount and hammered. At first I was trying to visually find the bad parts and try to hammer them out, but then at the end, I realized that the mount was not just off-shaped, but was kind of too small for the name ring, so I just started hammering around the entire ring by hammering, then turn the ring slightly, then hammer some more.

The (now, somewhat mangled) name ring eventually was able to screw into the filter ring mount:



and I was also able to get a filter to screw into the mount, kind of (it was VERY tight):

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