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Lens and Optics
Loose Inner Lens Bayonet Mount


If you have a Jupiter-8 or Helios-103 that seems to be loose while mounted on a Kiev body, here is an easy fix.

To diagnose a loose inner bayonet mount, press down on the lens release tab as indicated by Yellow Arrow and just wiggle the lens back and forth as shown by Blue Arrow. Without the lens release tab interfering there should be some friction present. If the lens is all sloppy and loose then we need to remedy this as the lens is not being held firmly in place.


First a little preamble. The edge indicate by Yellow Arrow is the lens seating surface. This is the edge that contacts the legendary "flange" on the camera body. The tab indicated by the Blue Arrow, and especially the edge indicated is what actually holds the lens in close contact to the mount.


On the other side the lens seating surface is indicated by the Blue Arrow on the top of the flange. The tab on the lens engages under this flange as indicated by the Yellow Arrow. If for some reason the tab on the lens is a bit bent then the lens will not seat down on the top of the flange surface.


This is a super-easy fix. Just use a very fine tipped slotted screwdriver and use it to force the mounting tab towards the lens seating surface. This effectively pinches the flange on the camera mount between the lens seating surface and this tab. Put your lens back on the camera, it should be nice and tight now.


June 05, 2006