A couple of months ago I mentioned my LX focus problem, where the top and bottom of the screen were out of focus in opposite directions. It proved surprisingly difficult to deal with, although the cause and solution turned out to be simple in concept and may be of interest.
I took it for a service and was told it was an unusual problem - an ominous start, as the service didn't sort it. I took it back, and it turned out that the repair technician had trouble seeing the focus on the screen and relied on the split image. He then adjusted the angle of the screen holder and there was a small improvement. However the screen holder was left dramatically tilted upwards, which didn't seem right. As suggested by several of you, the most likely option was that the mirror was misaligned. I noticed it appeared to sit higher than the mirror on my other LX, and the adjustment lever was also higher. I realised that an incorrectly aligned mirror would also explain why I sometimes cut off the top of pictures - perhaps not just my incompetence! So, having scanned the internet and PDML archives for information ... I printed out a target of concentric rectangles and made a "ground glass" screen consisting of perspex (plexiglass) that sat on the outer film rails with magic tape strips facing forwards, ie approximately in the film plane. As predicted, an image that was perfectly centred in the viewfinder sat too low in the film gate. Adjusting the mirror position is a nightmare, as the mirror stop is spring loaded and its resting position is held by a lever that has a pivot and locking screw. Over a couple of hours the mirror position varied wildly in either direction, but my technique improved and eventually I got it adjusted spot-on without either dropping the screwdriver on the shutter curtain or irreversibly damaging the screwheads. In comparison, the screen adjustment was simple as it can be done incrementally. A slight complication is that one of the four screws is about halfway down one side - the others are in the corners. This is fine if you want to move it without changing the angle, but requires some calculation if it needs to be tilted. However within a short time it was level, in focus right across its plane and the infinity focus was set. I took some photos of an angled target (as described in http://www.photo.net/learn/focustest/) and will use that to fine tune the adjustment. Relief! Further relief when I checked my other LX and found its mirror angle was perfect - I had had that one serviced at the same time. I'm sure the focus problem originated from bad service work before I had the camera. The repair guy pointed out that both cameras were missing seals and that the mirror buffers were non-standard. It's a pity he didn't think to check the mirror adjustment. Now back to actually using them! thanks to all for your helpful suggestions Alistair
