A7/A7R Light leaks reported + White Orbs issue?

Started Feb 8, 2014 | Discussions thread
Helen Veteran Member • Posts: 5,936
Re: Leak confirmed on my A7 (1 photo)

GaryW wrote:

MisterHairy wrote:

GaryW wrote:...

Even if you take any long exposures, you'll be fine, as long as you don't shine a flashlight around the mount. This appears to be a completely artificial problem.

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Gary W.

I see a surprising amount of "roll" between the 55mm lens and the a7r at the mount. One or other is not flat. The lens can swing sideways slightly, opening a gap of a fraction of a mm between the lens and camera mounts. However, 30s high ISO exposures with the lens cap on and a very bright LED lamp shining at the affected parts of the mount gives me nothing but black frames. I see movement but have no light leak.

Well, that just adds more confusion, doesn't it? Movement sounds bad -- I suppose it could affect the focus.

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Gary W.

I don't know whether it's relevant, but if you look closely at the E-mount, you will see that the three "claws" of the bayonet in the body mount are black.  This is a hybrid construction (i.e. rather than one-piece construction) that originally came in on Minolta's film bodies around 2002 (previously the bayonets been all-metal and sometimes on cheaper, later models all-polycarbonate, like the current A58 is) - the metal seating ring is screwed on top of the claw assembly.  This construction style carried on with Sony cameras since they inherited the A-mount from Minolta and they appear to have done similar with the E-mount too.  As far as I know, those claws are engineering polycarbonate or similar, so I would think that there could be some inherent flexibility in them.  Mind you, when I dismantled a film Minolta once, I found the claws were part of the outer front plate - in that case, they were polycarbonate like the rest of that component, but given the different construction of the A7 and A7R, it *might* mean that the claws are magnesium alloy for the A7R, and polycarbonate for the A7.  Or not - it could be a separate ring carrying the claws...

Canon uses a similar construction for its body mounts up to and including the EOS 100D - the 700D switches to all-metal.

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