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Vivitar (komine) 400mm f5.6 disassembly
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PostPosted: Wed Nov 28, 2018 6:40 pm    Post subject: Vivitar (komine) 400mm f5.6 disassembly Reply with quote

I am cleaning this lens - fungus. Front end was easy. I am trying to figure out how to get at the rear group. This lens block focusses ie whole optical assembly moves. The rear group is in too deep to access from the mount end. It is clear I need to separate the lens at the helicoid. I am not sure if this is a double helicoid or just a set up with sliding rails that prevents the front end rotating.
I thought at first it might be like a soligor, that the focus sleeve would slide up out of the way once the 3 grub screws (one is arrowed in pic) under the rubber grip had been loosened. Not the case: the focus rotates freely but doesn't move up or down.
Not sure what to do next. I am wondering if I should rotate the focus to cfd, then loosen the grub screws, move the sleeve all the way back round to the infinity stop, retighten the grub screws and rotate again to the cfd stop...
Any ideas?

Update. I found this thread:


So Actually I could separate the lens at the tripod mount. But then this guy couldn't reassemble!

PostPosted: Wed Feb 13, 2019 5:18 pm    Post subject: Reply with quote

I swapped messages with the poster of the thread i linked to. he never succeeded in fixing his lens. Rolling Eyes

PostPosted: Fri Apr 16, 2021 4:53 pm    Post subject: Cleaning a vivitar (komine) 400mm f5.6. Reply with quote

I have now had some success with this lens.

The front end elements can be cleaned just by removing the nameplate. There is a single grub screw that looks like it should allow the unscrewing of the whole front end, but considerable effort with a couple of strap wrenches didn't begin to shift mine. The nameplate was also stiff, but some acetone and elbow grease did the trick. There are three spaced elements and two spacer rings. Take care removing them and, particularly, replacing: very easy to jam one at an angle, or fail to seat something properly all the way in.
The rear end was what concerned me. I had found this post on photrio.com forum as mentioned above:


The poster, Peter K, had failed to get his lens back together again. The method is certainly the right one, this is how the lens is put together. Accessing the rear elements, fixing any looseness in the joint near the helicoid (which is what Peter K was doing), lubricating the aperture ring, all require taking off the rear end like this.

- The 3 screws are hidden under the rubber grip. (pic 1, 2). No need to remove the mount etc (at least not with PK).
- The rear end now pulls off. Ease it away gently so you can see the spring that needs to be unhooked (pic 3 ).
- Once the spring is off and the rear end pulled off completely the rear group can be easily accessed - it unscrews as a unit. I didn't need to go any further with mine, the fungus etc was on the external surfaces. I think the aperture ring is accessed by removing the rubber and the loosening some grub screws.
Pics 4, 5 show the slot, and the button that engages with it, that Peter K had such difficulty with.
- Now Peter K is going to hate this, but I simply didn't have a problem. Paper clip to re-engage the wee spring, the rear end eased back on, line up the screw holes (I had white dots of eraser fluid marking the spots), little bit of wiggling and flicking of the aperture lever, slight click, voila, all set! Replacing the screws was a little fiddly due to the necessity of holding the rubber back at the same time.






PostPosted: Fri Apr 16, 2021 6:35 pm    Post subject: Reply with quote

Like 1 small

PostPosted: Fri Sep 24, 2021 9:23 pm    Post subject: Reply with quote

Channeling Monty Burns: Most Excellent! I have one of these that I'm trying to resurrect. The advice about the front elments is correct: Easy to get the second and third one cocked. The third one fits into the spacer, but will fall out when you go to install it or fall forward if you try to push the second one with the lens big end down. Just be patient.

I'm going to pick a day when I have the time and good light before I attack opening the back end up; need to make sure I can see and have a morning's level of patience.

PostPosted: Tue Sep 28, 2021 4:24 pm    Post subject: Reply with quote

And a quick update:

My version of this lens is a Canon mount. I separated the two halves...on my version there was no spring to attend to. I suspect that made it simpler. The rear element complex unscrewed easily. There was a retaining ring on the rear. The last element came out after that was removed. There had to be some sort of retaining system for the front of the two elements, but I couldn't get it apart. So, I just cleaned it where it sat, cleaned the rear element, reassembled the complex, and put it back in place in the front half of the lens.

Using the advice above, I set the aperture to f5.6, lined the pin and the slot up as best as I could (which also corresponded with the screw holes being aligned. After the two mated, a couple quick clicks of the aperture ring and I heard the slot and the pin connect. Bob's yer uncle.

Many thanks for the guidance.

Channeling Lee Corso: Not so fast, my friend...

I failed to look at my disassembly pics, and managed to reinstall the tripod ring facing in the wrong direction. It works/balances either way, and the way I did it looks like my other telephotos, but not as Komine intended. Back apart, back together...Carry on.