Replacing a broken mount - Panasonic 14-140 v2

Discussion in 'Native Lenses' started by greenjp, Sep 1, 2016.

  1. greenjp

    greenjp Mu-43 Regular

    May 15, 2014
    Howdy folks,
    After a few years with the system (started with G3 and now have a GX7) and a small collection of lenses (20 1.7, 45 1.8, 14-42 v2, 45-150, and an old Hexanon 135 3.2 for fun) I decided that while I liked both the 14-42 and 45-150 I found it sort of annoying to have to switch. Enter the 14-140 v2 which seemed to fit the bill as a replacement for both. Being something of a cheapskate and somewhat adventurous, I found myself buying one that was advertised as working properly and with clean glass but with a cracked lens mount.
    [​IMG]P1190901 by Jeff Green, on Flickr

    Got it and found that did work more or less properly, but that the mount damage was a little worse than anticipated. Posted some pictures a while back which seem to show a decentering effect consistent with a broken/crooked mount.
    I disassembled the mount and discovered that not only was the mount broken, but one of the three plastic tabs within the body that the mount attaches to was sheared off.
    [​IMG]P1190902 by Jeff Green, on Flickr

    [​IMG]P1190903 by Jeff Green, on Flickr

    [​IMG]P1190914 by Jeff Green, on Flickr

    [​IMG]P1190911 by Jeff Green, on Flickr

    [​IMG]P1190908 by Jeff Green, on Flickr

    So much for metal mounts - as the popular LensRentals post makes clear it's not just the mount but the complete internal construction that matters. Turns out that while you can order the mount itself for ~$53, the internal part of the lens that it attaches to is basically the entire lens assembly and is not offered as a replacement part.
    Undaunted I ordered up a new mount from Panasonic (actually their spares supplier here in the US, Encompass), along with a hood for $75 total delivered. Annoyingly, though the site said the mount was a 10 day backorder, it actually took about 6 weeks to arrive.
    Due to the broken mounting tab the install of the new mount required some extra effort. I basically got it all lined up, verified that the new mount fit properly flush to the body, and then used a combination of crazy glue (more or less instant setting) and JB Weld (~24 hr set time) on the broken tab, the two small locator pins, and about 1/4 of the mount seating surface in the area of the broken tab. The other two screws held just fine. Put that together and set a book on top of it to hold it tight until everything set firmly.

    [​IMG]P1190916 by Jeff Green, on Flickr

    After a day I checked it out and it looks pretty good, the mount is secure and evenly affixed to the body. Of course the downside to this is it will be difficult or maybe impossible to remove the mount again in the future but that's OK as long as it works. And it does seem to work nicely. I think I can still see a bit of residual softness on the left edge when I zoom it in a lot, but at normal sizes on my 1920x1080 monitor it's undetectable. And the center sharpness seems to be great.
    [​IMG]P1190971_DxO by Jeff Green, on Flickr

    [​IMG]P1190968_DxO by Jeff Green, on Flickr

    [​IMG]P1190938_DxO by Jeff Green, on Flickr

    [​IMG]P1190921_DxO by Jeff Green, on Flickr

    Total outlay was $265, so a good $150-200 savings off the going rate for a good example. Hoping to get about half that for my 45-150.
    So if you have a broken or otherwise malfunctioning lens and a decent set of precision screwdrivers, I definitely recommend taking it apart. If nothing else you'll learn something about how they're designed and assembled.

    • Like Like x 6
  2. adamsmt2013

    adamsmt2013 Mu-43 Regular

    Aug 31, 2013
    Be careful with super glue and optics. A friend of mine ruined a Nikon lens this way because it attacked the lens coating.
    • Like Like x 1
    • Agree Agree x 1
  3. greenjp

    greenjp Mu-43 Regular

    May 15, 2014
    Indeed, I was mainly worried about an errant drop of glue getting on or accidentally scratching the rear element, which is just hanging out there when you've got it disassembled. The rest of the lens is just plastic and metal parts and PCBs so as long as I didn't glue my fingers to it I wasn't worried :)
  4. pellicle

    pellicle Mu-43 All-Pro

    Feb 10, 2010
    Southport, OzTrailEYa
    Real Name:
    Gotta worry about vapors too