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Super-Multi-Coated Takumar 200mm F4 stuck aperature?
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PostPosted: Fri Aug 10, 2018 5:55 am    Post subject: Super-Multi-Coated Takumar 200mm F4 stuck aperature? Reply with quote

I bought a really clean copy of this lens off ebay. It appears to be the later version with the little barely protruding pin that you need to push to switch between auto and manual aperture control. The switch itself moves just fine, as well as the aperture ring, they both click and move normally. But the aperture blades are not moving at all whether I push the other taller pin in or not. When I move the aperture ring, the tab on the rear does move along with it. Am I doing something wrong here?

I intent to adapt the lens to use on a Sony alpha camera, so I got an adapter for it as well. All my other M42 lenses (16 at last count Razz) did not have this problem. Could the mechanism inside somehow became unlinked/unhooked? I rather not open it if I don't have to since there are no dust inside that I can see yet. I've repaired many lenses previously, so if I have to, I'll open it it. Just thought maybe I missed a step somewhere on these newer Takumars.


PostPosted: Fri Aug 10, 2018 6:36 am    Post subject: Reply with quote

Welcome rcboosted

The extra little pin depressed allows auto/man switch to move from auto to man. When auto/man switch is in auto position, pressing long m42 pin should close aperture to size indicated on aperture ring. So to work in auto, switch needs to be in auto position, aperture ring set to other than f/4, depress m42 pin. M42 pin is spring loaded to return to open aperture. In man position, aperture should close and open when turning aperture ring.


PostPosted: Fri Aug 10, 2018 7:06 am    Post subject: Reply with quote

Thank you for the welcome!

I guess the aperture mechanism is broken then. When switch is in Auto position (the word auto exposed), I turn it to F22, push the big pin in at varying degrees, no change. I set it to manual, turn the aperture ring, nothing happens. Time to tear into this lens I suppose. Thank you for the clear and details procedure.


PostPosted: Fri Aug 10, 2018 3:15 pm    Post subject: Reply with quote

I doubt seriously your 200/4's iris mechanism is broken. It is much more likely -- a virtual certainty even -- that what's happened is lubricant from the helical has migrated down to the iris, coating the blades. If you can force them closed at all, you would see some of this oil. The remedy is to dismantle the lens to the iris, clean the blades with solvent until they snap open and closed cleanly with no hesitation, then reassemble. Note that iris blades must be completely dry. No lubricant of any sort must be used on them.

I would thoroughly clean the iris with naphtha -- my first choice -- or a strong alcohol, either isopropyl or denatured -- my second choice -- and I mean thoroughly. Make sure there is no more lubricant left anywhere in the iris mechanism before reassembling the lens. Also note that it might not be necessary to remove the iris assembly from the lens to clean it. If at all possible, I like to leave the iris mounted in the lens and clean it there. I hate futzing with individual blades.

Naphtha is also known as cigarette lighter fluid, as is used in the old Zippo-style lighters. You can buy a bottle of it, or you can do like I do and buy a qt. can of it at a big box store for about eight bucks. That can will last a lifetime, plus naphtha, being an excellent solvent, is good for a number of different tasks, including filling Zippos. Cool


PostPosted: Fri Aug 10, 2018 10:41 pm    Post subject: Reply with quote

cooltouch wrote:
I doubt seriously your 200/4's iris mechanism is broken. It is much more likely -- a virtual certainty even -- that what's happened is lubricant from the helical has migrated down to the iris, coating the blades. If you can force them closed at all, you would see some of this oil. The remedy is to dismantle the lens to the iris, clean the blades with solvent until they snap open and closed cleanly with no hesitation, then reassemble. Note that iris blades must be completely dry. No lubricant of any sort must be used on them.

I would thoroughly clean the iris with naphtha -- my first choice -- or a strong alcohol, either isopropyl or denatured -- my second choice -- and I mean thoroughly. Make sure there is no more lubricant left anywhere in the iris mechanism before reassembling the lens. Also note that it might not be necessary to remove the iris assembly from the lens to clean it. If at all possible, I like to leave the iris mounted in the lens and clean it there. I hate futzing with individual blades.

Naphtha is also known as cigarette lighter fluid, as is used in the old Zippo-style lighters. You can buy a bottle of it, or you can do like I do and buy a qt. can of it at a big box store for about eight bucks. That can will last a lifetime, plus naphtha, being an excellent solvent, is good for a number of different tasks, including filling Zippos. Cool


I had suspicion that the blades were oiled up and got stuck. But what happens when it's stuck and I rotate the ring? From other lenses I've seen, there's a fork of sort that moves a lever. So if the blades are stuck and the aperture ring rotates freely, could the fork have broken? Probably just came loose I guess.

In the past, i've used electronic contacts cleaner. It has done a great job for me since it evaporates cleanly without a trace. Have you had experience with them or know of any negatives of using them?


PostPosted: Sat Aug 11, 2018 6:01 am    Post subject: Re: Super-Multi-Coated Takumar 200mm F4 stuck aperature? Reply with quote

rcboosted wrote:
I bought a really clean copy of this lens off ebay. It appears to be the later version with the little barely protruding pin that you need to push to switch between auto and manual aperture control. The switch itself moves just fine, as well as the aperture ring, they both click and move normally. But the aperture blades are not moving at all whether I push the other taller pin in or not. When I move the aperture ring, the tab on the rear does move along with it. Am I doing something wrong here?

I intent to adapt the lens to use on a Sony alpha camera, so I got an adapter for it as well. All my other M42 lenses (16 at last count Razz) did not have this problem. Could the mechanism inside somehow became unlinked/unhooked? I rather not open it if I don't have to since there are no dust inside that I can see yet. I've repaired many lenses previously, so if I have to, I'll open it it. Just thought maybe I missed a step somewhere on these newer Takumars.


I also have this lens with a sluggish iris (in my case it is not completely jammed). Its not uncommon in old Takumars and unsurprising given their age. The problem is they are not especially valuable lens and the cost of having one serviced professionally outweighs the value of the lens.

Does anyone have a comprehensive explanation of how to disassemble this lens to get at the iris for cleaning? (preferably with video or diagrams). I tried a few years ago and found a few threads where it was discussed but not in enough detail for me to tackle the job. From memory I got the front element assembly off (its easy IIRC) but then got comprehensively lost as the slightly vague advice that was given was in conflict with what I was finding with my copy of the lens.

For now I have left it - since my copy closes (slowly) I can use it still as an instantaneous response is not required when mounted via adapter on a mirrorless camera. Never the less it would be nice to fix it.

Ideas that might help both of us?


PostPosted: Sat Aug 11, 2018 7:26 am    Post subject: Reply with quote

I have never done it, but here is a video showing how
Repair takumar 200mm utube
https://youtu.be/uA5GW-ba3Jc


PostPosted: Sat Aug 11, 2018 11:25 am    Post subject: Reply with quote

Oldhand wrote:
I have never done it, but here is a video showing how
Repair takumar 200mm utube
https://youtu.be/uA5GW-ba3Jc


Thank you. This is exactly what is needed. Now whether I am brave enough to attempt it is the question........


PostPosted: Sun Aug 12, 2018 11:08 am    Post subject: Reply with quote

rcboosted wrote:
I bought a really clean copy of this lens off ebay. It appears to be the later version with the little barely protruding pin that you need to push to switch between auto and manual aperture control. The switch itself moves just fine, as well as the aperture ring, they both click and move normally.


What does the switch look like? I am only aware of two versions of this lens, the Super-Multi-Coated and the Super-Takumar. I have the Super-Multi-Coated version and it looks like this:



PostPosted: Sun Aug 12, 2018 7:11 pm    Post subject: Reply with quote

D1N0 wrote:
rcboosted wrote:
I bought a really clean copy of this lens off ebay. It appears to be the later version with the little barely protruding pin that you need to push to switch between auto and manual aperture control. The switch itself moves just fine, as well as the aperture ring, they both click and move normally.


What does the switch look like? I am only aware of two versions of this lens, the Super-Multi-Coated and the Super-Takumar. I have the Super-Multi-Coated version and it looks like this:



that looks exactly like mine. even the code on the bottom of the switch matches mine.


on a different note, i found the same youtube video as well, and i was able to take mine apart to clean the blades. they were completely soaked in oil as suspected. i could not get to the actual blades since the video didn't cover that pat and i couldn't figure out how to open it myself. it looks like i might be able to grab the helicoid part and unscrew the whole thing, but i didn't want regrease the whole thing. copious amounts of electronic contact cleaner did the job nicely as it sits. no doubt the oil will return, but i'm satisfied with it for now. blades move freely without oil.

the video really made it easy to put it back together. instead of having to guess where to start the helicoid thread, i juts line up the maks indicated. now i'm going to wait a day before final reassembly to make sure all the cleaners have evaporated. note on the fork that moves the blades. it's designed in a way so that when the blades are wide open, closing the aperture won't damage the mechanism.


PostPosted: Sun Aug 12, 2018 10:37 pm    Post subject: Reply with quote

Congrats Whoo Turtle


PostPosted: Mon Aug 13, 2018 4:12 am    Post subject: Reply with quote

It's great to hear of your successful repair! Just in case you encounter this issue again - and you will - collecting Takumars is habit forming - here's another tip. Sometimes you clean the blades and the diaphragm is still sluggish or inoperative. I have found that the problem can also be a slightly bent actuating pin (the long pin that sticks out the back). It usually can be straightened through the judicious use of needle-nosed pliers. i think the pin can get bent if the lens is stored without a rear lens cap, or if the lens is dismounted from the camera improperly. I usually check this first now, before I attempt a disassembly.

Enjoy using the lens!

P.


PostPosted: Tue Aug 14, 2018 8:02 am    Post subject: Reply with quote

pdccameras wrote:
It's great to hear of your successful repair! Just in case you encounter this issue again - and you will - collecting Takumars is habit forming - here's another tip. Sometimes you clean the blades and the diaphragm is still sluggish or inoperative. I have found that the problem can also be a slightly bent actuating pin (the long pin that sticks out the back). It usually can be straightened through the judicious use of needle-nosed pliers. i think the pin can get bent if the lens is stored without a rear lens cap, or if the lens is dismounted from the camera improperly. I usually check this first now, before I attempt a disassembly.

Enjoy using the lens!

P.


Habit forming is an understatement. I have tons of other MF vintage lenses too. Pretty much have an adapter for every mount out there except for Olympus and Leica M lol. Thanks for the tip, good thing I haven't ran into the bent actuating pin issue.

Thanks everyone who chimed in to help!