Forum: Monthly Photo Contests
08-09-2018, 05:24 PM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
08-09-2018, 05:23 PM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
08-09-2018, 05:23 PM
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I would like to nominate this photo
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Forum: Winners' Showcase
08-09-2018, 05:22 PM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
08-09-2018, 05:21 PM
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I would like to nominate this photo
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Forum: Winners' Showcase
07-10-2018, 06:07 AM
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I would like to nominate this photo
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Forum: Troubleshooting and Beginner Help
08-26-2017, 11:10 AM
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I just bought a vivitar serie 1 90mm f2.5 macro with the dedicated extension tube. The lens come in pk mount, I'm a canon user and I'm waiting for the adapter to come.
I was examining the lens today, it is in very good condition, but I noticed that the adapter has an aperture ring, when installed on the lens, this ring can only close the aperture. It is not working in both ways. To open bach the aperture I have to use the ring on the main lens.
Is it a defect of the adapter? Am I installing it not properly? I'm not familiar with pk mount...
Thanks for the help.
Roberto
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Forum: Monthly Photo Contests
03-17-2017, 01:02 AM
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Forum: Maintenance and Repair Articles
12-10-2016, 03:41 PM
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First of all I hope I'm posting in the right place.... sorry if it is not the case, I'm new to this forum and still not very familiar with it.
Second... sorry for my bad English.
I recently acquired a Super Takumar 135 f3.5, with M42 mount with just the auto iris pin from the bay, and when it arrived it was very dirty and kind of smelly, so I decided to clean it, but when I got started I went all the way through.
Disassembling starts in the front of the lens. - Unscrew the name ring with a cylinder made with rubber, or has I did using a metal caliper end pointing it on two of the letters.
- You should see the retaining rings for the front lens, actually there are two of them. Using a lens spanner wrench could be tricky because the ring has holes only half of its thickness. I found it easier to use the caliper.
- Unscrewing the first ring can make two thing happen: the first of the main lens retaining ring come loose or the full block of the front elements come loose. It is probably better if the second possibility occurs. If it does not you have to take out the first ring and use the second to unscrew the front elements group.Pay attention that if the first retaining ring is unscrewed then the first lens of the front group is free, if you flip the group upside down it could come out.
- Once the first lens group is out you can see the three screw that are holding the filter ring. Unscrew them and take out the ring.
- Unscrew the three screws holding the focus barrel paying attention that under each screw there is a tiny copper washer.
- Under that there are other three screws with copper washers that are fixing the focus barrel to the helicoid. If you can mark the position of the helicoid before unscrewing them, because how they are set is your infinity focus. If you cannot mark them or you forget, it is not a big deal, but you will have to re-calibrate the focus when you will assemble back the lens.
- Remove the scales ring (the one with ft, m and the aperture) loosening the three retaining screws.
- Now you can extract the aperture ring paying attention not to loose the little metal ball the is under it.
- At this point I took out the rear lens, probably it could also be done at a later moment. To do this you have to go through three retaining rings. Once you unscrew the last ring the lens is free to come out. Mine was a little stuck but at the end came loose. You can help the process pushing a little on the other side with something soft that would not scratch the glass.
- Take apart the aperture blades barrel and the bottom barrel where are all the mechanical movements and springs unscrewing the three screws showed on the picture.
- Now remove the aperture blades command pole, it is not strictly necessary but is making the aperture barrel more manageable.
- To have access to the blades you have to remove the inner metal ring above the blades, that is kept in position with three retaining screw. Once you remove the screws you have to find a way to slide the metal ring out of the barrel. I did it inserting two fingers inside and trying to rotate it.
- Finally you have reached the aperture blades. They are set in position with a hole and a pin, the hole is resting on a pin on the command ring and the pin on the blade is resting on a hole in another ring. When the command ring is moved the blades open and close with a sort of lever mechanism.To put back the blades after having cleaned them with lighter fluid has been a pain, also because it was my first time. It took me more than an hour to figure out how to insert them properly. The trick is to have the rings in the fully open position, put the first blade in, then slide the second under the first clockwise until you can insert the hole in the pin that is hidden by the first blade, the third has to be slide in under the second and so forth. You definitely need some tweezers for the job.
- Once you have reinstalled the blades you can follow the process in reverse to reassemble le lens. When you reinstall the aperture blade barrel, take care of aligning the command pole with the appropriate groove in the command mechanism.
Since I was there I also took the chance to clean all the mechanics from old grease replacing it with new one.
The all process was long but not too difficult, reassembling the lens the only problems I had was that the spring that was holding in place the aperture mechanism went out of place, so the aperture blades were not moving properly, and I spent an hour laying on the floor of my kitchen looking for the little metal ball that is under the aperture ring.
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Forum: Welcomes and Introductions
11-26-2016, 11:20 AM
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Hello to everybody,
my name is Roberto, and actually I'm not a pentax camera owner:fedup:, but it is a while that I follow this forum and its reviews on third party lenses, so I thought to subscribe and give my newbie two cents.
I recently acquire a taste for old manual lenses and I started buying few online. I have to say that I'm surprised with the quality you can get with cheap old lenses:). This is thanks to you and your very useful reviews.
I hope you don't mind having a canon owner in your members list:o.
Take care.
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