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03-02-2011, 03:15 PM   #1
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S-M-C Takumar 50mm/1.4 distance scale problem

Hi there,

I recently acquired a S-M-C tak 50/1.4 and while I really like this lens, the distance scale stopped working after only a few weeks of using it.

The lens itself is in good condition, no fungus, oil on blades or anything. But now when I focus the distance scale doesn't move at all, and I hear a crackling sound inside. The lens still works as it should, focuses fine and the aperture rings works nicely as well.

It took me quite some time to get this lens, and I payed $160 with shipping for it, I like it a lot but it saddens me a lot that something on it failed so quickly .

Is there anyone who had similar experience with a lens and could help me in any way...?

Also, I dont need the scale meter really as I bought it for portraits and close range shooting, but If this problem will mess the lens altogether eventually then there is something to get worried about...

Any help on the matter is much appreciated.


Thanks,

03-02-2011, 04:46 PM - 4 Likes   #2
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This is a typical problem for the version with the rubber focus ring, the SMC Takumar, but it can happen to the older ones too. It is really irritating because it's a minor issue, sometimes sounds and feels like major damage, and requires some disassembly to fix.

The distance scale is engraved on a thin strip of aluminum, then wrapped around the base of the focus ring. What's happened is the glue failed on the distance scale. Sometimes just the ends come loose, creating a horrible grinding feel when focusing as they rub against the outer lens barrel. This is pretty hard to ignore, so in one way you're lucky. You can just use the lens as is without problems. You can check to see if I'm right; you should be able to move the scale without focusing.

You can fix it yourself. The short version of the steps:
- focus to infinity
- put some tape on the focus ring and mark the tape where the orange diamond is
- use a friction tool to remove the "name" trim ring
- use a small screwdriver to remove the 3 screws holding the filter ring on
- make sure you're still at infinity and remove the 3 screws holding the focus ring on
- take off focus ring and there's the aluminum strip.
- clean off the old glue with solvent
- reglue. Make sure the distance scale is glued back in the same place it was before. A rubber band can hold it in place while the glue dries.
- reinstall the focus ring so that its infinity stop is where it was before
- check infinity focus - it can be adjusted if it's wrong by loosening the screws, shifting the ring, tightening and rechecking.
- reinstall the filter ring and trim ring

Post or PM me if you need more complete instructions or photos. My Super-Multi-Coated 50/1.4 uses phillips #00 screws but you might find slotted screws on older lenses.

Here's a photo, the best I have of the focus ring and scale together.

03-02-2011, 05:04 PM   #3
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Just 1 More, Dave: Thanks for making this contribution to help a Forum Member. This is the kind of stuff that heppened every day a few years ago and I'm delighted to see a post like this again!

Paul
03-02-2011, 06:45 PM   #4
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Thanks a lot for the reply, but I'm afraid Ill have to pm you for more instructions as Ive never disassembled a lens.

Also I have no idea what a friction tool is .

And yes, I can move the distance scale without focussing, and it seems to go little up and down along the lens barrel.

If I m not able to fix this, the lens will work fine and that scale ring wont damage anything?


Thanks

03-02-2011, 07:00 PM   #5
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QuoteOriginally posted by Just1MoreDave Quote
My Super-Multi-Coated 50/1.4 uses phillips #00 screws but you might find slotted screws on older lenses.

Here's a photo, the best I have of the focus ring and scale together.
They might look like phillips #00, and a phillips #00 might work if the screw isn't tight. But they are JIS and if the screw is tight you might strip it. If you are going to be opening Japanese lenses you should invest in a JIS bit set. Micro-Tools has everything needed to work on lenses.

Micro-Tools, Camera & Watch Repair Tools - Home
03-02-2011, 10:00 PM - 1 Like   #6
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QuoteOriginally posted by boriscleto Quote
They might look like phillips #00, and a phillips #00 might work if the screw isn't tight. But they are JIS and if the screw is tight you might strip it. If you are going to be opening Japanese lenses you should invest in a JIS bit set. Micro-Tools has everything needed to work on lenses.

Micro-Tools, Camera & Watch Repair Tools - Home
my opinion/experience:

To tell the truth, I don't know how to tell the difference. I have the JIS screwdrivers but have only used them for mount screws, especially on Pentax-A or later lenses. In my experience, mount screws are tough, and sometimes the screwdriver tip will twist off first.

I know I have seen slotted screws used on this lens. My current copy has some kind of cross-point variation. With stubborn slotted screws, I can grind a tip to fit perfectly, so I don't worry about buying the right type.

Just looking at the filter ring screws on the Super-Multi-Coated Takumar 50mm f1.4, a screwdriver can't meet the screw at exactly a 90 degree angle. I don't think a perfect fit will be better here.

For the focus ring screws, make sure you have a long thin blade. Sets with interchangeable tips usually are not long/thin enough to access the screws. In this lens, the blade needs to be thin for maybe a half-inch, 12mm. Longer lenses like 105s and 135s are worse.
03-03-2011, 04:28 AM   #7
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https://www.pentaxforums.com/forums/maintenance-repair-articles/119344-cross-...s-caution.html
03-03-2011, 12:15 PM - 4 Likes   #8
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Some more information on this repair

I did some typing last night and took some more photos this morning, so here's a more comprehensive guide. First, a photo of my lens. Write down the serial number - I'll be sure to disclose my many repairs to this lens if I ever sell it.



The first step is removing the ring with the serial number and lens name on it. It unscrews using the filter threads. If the threads aren't clean, I use an old toothbrush on them. The threads can't be bent or damaged either. The friction tool is the actual professional tool, available at Micro-tools. It's a series of rubber rings that fit different filter sizes on the lens. I use the thing on the left in this photo:



It's a plumbing part. I can resize it to fit any lens. It has worked for me. Anthing that fits well against the ring, grips it well, doesn't touch the glass, and you can grip will probably work. You'll see some lenses on eBay with holes drilled in the ring for greater leverage; some people get impatient.

Here's a photo with the trim ring removed:



The red arrows are the screws holding the filter ring on. If your lens is a 55/1.8, it looks something like this, with six screws, three screws in little cutouts. Don't remove all six screws, only the three screws marked with arrows here.



With the filter ring removed, your lens looks something like the next photo. There are three screws holding on the focus ring, two visible in the photo and marked with red arrows. This is a good spot to mention that if you loosen these screws, you may have to realign infinity focus. If you want to avoid that, set the focus to infinity now and don't move the ring. Green arrows mark holes for the filter ring screws.



Here's the lens with the focus ring removed. The brass ring controls focus. The screw marked with an arrow is the stop screw. Steps in the focus ring run into the screw.



These are the steps in the focus ring, marked with green arrows:



Here's a photo of the problem, the unraveling distance scale. The scale has a little spring tension, and the glue sometimes only lasts for 35 years!



I thought about this last night: how can you get the scale back to the original spot? They thought of that at the factory, conveniently providing a small index mark to line up with the step in the focus ring, hidden from normal view.



After taking a lens apart this far, it's not much trouble to go further, perhaps for cleaning and regreasing the aperture ring. You'll need a tiny common screwdriver, for three screws you can see on the ring with the engraved depth of field scale and the orange diamond. (If you could remove this ring without all the other steps, it would be great, as the distance scale is right behind it. But it can't be removed until you take off the focus ring, unfortunately. The ring is holding the aperture ring in place. Loosening the tiny slotted screws allows you to lift the ring off, but don't hold the lens by the aperture ring or that will come off too. There's a spring-loaded ball bearing pinched between the aperture ring and lens body, below the orange diamond, that might try to escape. It makes the aperture ring click at each stop.

Reassembly is just reversing the steps and being careful. I normally put all three screws in when reattaching the focus ring, but only tighten one. Then I check infinity focus. I have an old film camera that I use for this, with a big split-prism viewfinder. I also have a nice view of a distant mountain range - anything more than a few miles away is fine. Maybe it doesn't need readjustment but this is the time to check. If you suspect that the focus ring moved on you in disassembly and aren't sure what position it's in now, look at the photo showing the stop screw. See how the screw holes in the brass ring are under the tabs for the filter ring screw holes? That's "beyond infinity" - the brass ring can't turn any farther that way, and the front element is as deeply recessed as it will go. That's a good starting spot for readjustment.

Then put the filter ring on, then the trim ring, and take photos.

03-03-2011, 03:18 PM   #9
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WOW! he effort you took is just amazing!

Now noone can go wrong with this one.

Thanks a lot!
03-03-2011, 03:28 PM   #10
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Bookmarked !

Excellent tutorial.
03-03-2011, 08:52 PM   #11
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Nice tutorial, Dave. Well done.

This is certainly one for the General Technical Troubleshooting section.

H2
08-16-2011, 08:26 AM   #12
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This thread is an example of why I stick wtih Pentax, this is a CULT!!!!!!!!! A damn good cult!!. Everything has been done to every lens by someone, and they share, great.
09-09-2011, 02:37 PM   #13
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Well, I recently purchase the SMC Tak 50mm f1.4 and before being sent to me, the seller told me he had to to do the regluing of the scale strip. He used this procedure and I am happy. The lens is just fine, another advantage of using Supre Taks.
10-27-2012, 03:22 PM   #14
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Sorry for reviving this old thread, but I'd like to know what adhesive is best to use to put the distance scale back in place - ideally one that can be removed in case I do anything wrong.
10-27-2012, 06:45 PM   #15
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Contact Cement would be my Guess But please do wait for people with more experience on lens repair to chime in........It can be released with the proper solvents but I do not know if you want those solvents around a coated lens........
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