Fixing zoom lens

Discussion in 'Accessories' started by admiralblur, Feb 25, 2003.

  1. I have an old Vivitar zoom lens that I would like to fix myself
    because a) it's not worth the money it would cost to have a
    professional fix this thing and b) I don't have any money .

    I know someone is going to tell me to just buy a new lens, which I
    will soon enough, but if anyone has any resources out there for common
    problems with lenses or general self-repair I would love to check them

    It's a Vivitar 85-205 3.8 hooked up to a Minolta (pre-autofocus). The
    lens won't focus correctly past 3 or 4 meters, so I'm hoping that I
    could just adjust the focusing mechanism somehow. Any ideas out there?

  2. Just buy a new lens. (There, it's said). Seriously, if you can take the thing apart and put it back together without damaging anything or getting anything backwards, you'll probably be able to figure out the problem, too. Figure it's essentially worthless right now, so have a whack at it and you can't lose. Seems like I recall someone recommending to video the disassembly to help with reassembly.
  3. There are some books on camera repair that cover many typical zoom lenses. I bought a couple on Ebay, just because I was interested. But by the time you pay for the books you will be along way towards spending the money to replace the lens. In fact, I bet you can get another used zoom lens in MD mount to fit your Minolta for less than the books cost used. These old manual focus Vivitars are nearly worthless on the used market.

    Anyway, the usual way into them is through the lens mount. Remove the 4-5 screws at the back of the lens, remove the mount and start working your way in. You will also have to remove the rubber grip on the zoom and focus ring(s) to get to the screw under them. You may be able to see the white cam followers in their cam cylinder slots. If you're really lucky, you might see a loose screw on one of these followers that is causing the cam to bind.

    The usual problem with a zoom or focus ring that will only go so far is a bent barrel or "cam." The "cam" in this case is a cylinder surrounding the lens core that has helical slots cut in it. There are usually two or three of these cams, and they usually have cam followers mounted on them as well. In Vivitar's case, "cam followers" are usually small white plastic squares that slide in the helical slots as the cam rotates.

    Anyway, you will likely find either a bent cam cylinder (bad news) or a cam follower that is binding due to its screw holder falling out (good news). Who knows, it might just be dirty or in need of a tiny bit of lubrication.

    Hope that helps.
  4. I know Jim doesn't make it sound exactly easy, but it's worse than that. My one attempt at this exercise was on an old Tokina lens, and I was horrified at the number of little pieces that began spilling out when I took the back ring off. I won't try it again.
  5. Zoom lenses are one of the less entertaining repair projects I've encountered. If the zoom or focus is binding, and in particular if the lens has been dropped, one of the slots in the outer barrel may be bent and binding the cam. You may be lucky enough to find the problem just under the rubber focusing grip... if so, the easy thing to do is to remove the sticking cam, make it littler by any convenient means until it can pass through the bent part of the slot, and put it back in. I didn't say this was the best, just the easiest.... it will get the lens back on the street.

    if you don't find the problem this easily, it's a combination of patience, care and luck. here's wishing you an adequate supply of all three!

    rick :)=
  6. One good tip - and I can't remember the source so apologies to the originator - is to use a video camera, or a digital camera, to record the taking apart. That way you'll know what goes where when it comes to reassemble the (repaired?) lens.
  7. As one who used to repair video camcorders for a living, my initial response is: go buy a new one. But, if you're up to it, here' some tips:

    1)No caffeine for at least 12 hours prior.

    2)Buy several plastic "fishing tackle" trays, with little compartments. Use paper labels for each set of screws you remove with a description of where it came from, and store them in each compartment seperately. Start from upper left in compartment, and number them in order as you remove them. Note that each set of screws may be different length/pitch/head style, and some may be machine screws, while others (threading into plastic) may be self-tapping.

    3)When you find the broken cam linkage, or lens mount ring thats crunched, go ahead and take the time to precisely re-assemble the unit in reverse order, just for the experience. Note that you will not be able to find any new spare parts, but another used lens may provide the answer.

    4)The next time you have to take a camera into a repair shop, and wonder why its taking the technician so long, now you'll appreciate why.
  8. Different people have different experiences to contribute:

    1) Without two cops of espresso coffee in the morning I can't even move my hands

    2) My Albinar 28-200 mm macro zoom lens fell from a chair and the two bolts that bear the Nylon rollers were broken. I disassembled the Albinar easily, took out the broken parts and re-assembled it before I took it to a repair shop. It was all done in 30 minutes.

    3) The man in the repair shop (a friend who originally sells and repairs Diesel engines for model aircrafts) disassembled it in 3 minutes, drilled two tiny holes and fixed the Nylon rollers with two little screws. Not an ideal solution but it works. The whole repair took about 30 minutes.

    4) This happened on the Canary Islands, the next specialised photo-repair shop being 2000 miles away. Guess how happy I was...

    My two cents to that subject may be outdated but I just came across this thread browsiing the web.


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