Mamiya 645 lens issue

[rubyfalls]

So, I posted about this problem a while back when it first started happening. My thoughts - and the consensus - were that I was simply hitting something when I flipped from landscape to portrait while shooting. I've ruled that out. Here is what is happening:

I am shooting with my 80mm f/1.9 (this does not ever happen with any of my other lenses). I compose, check exposure, and I see a solid 'LT' under the suggested speeds, the mirror is locked up, and the shutter will not release. It is as if I have switched the lens to M to check the dof OR locked up the mirror, but haven't actually done either of these things. The only way that I can get it to release/unlock is to flip to M and back to A on the lens and release the shutter. And of course I lose that frame. I am not hitting the timer either.

Any thoughts? Could it be something in the lens has worked loose? Or user error of some sort? Please let it be the latter...


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[MattKing]

The one factor that is particular to that lens is that it is more than one full stop faster than any other lens in the line.

I am wondering if your problem has something to do with the interconnection between the aperture setting on the lens and the metering prism.

I have one lens (a 110mm f/2.8) where that interconnection is finicky.

Are you using auto exposure metering when this happens? If so, try using manual exposure metering instead.

 

[rubyfalls]

The one factor that is particular to that lens is that it is more than one full stop faster than any other lens in the line.

I am wondering if your problem has something to do with the interconnection between the aperture setting on the lens and the metering prism.

I have one lens (a 110mm f/2.8) where that interconnection is finicky.

Are you using auto exposure metering when this happens? If so, try using manual exposure metering instead.

You know, I think this only happens on the rare occasion when I have it in AE. I'll clean all the connections carefully and run a test.

The only thing I have found on the interwebs regarding a solid LT has to do with attempting to lock the mirror when it isn't set to AEL. Sometimes I wish I had a better brain...


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[MattKing]

Remember that the connection that signals the aperture setting to the meter is a mechanical one - the Aperture Ring Coupling Pinon the metering finder needs to fit into the Exposure Meter Coupler of the lens (see the manual ).