pingflood,
It is really a quite simple conversion. The Olympus is 1/2mm further from the sensor then Pentax. The flange on a typical flange style m42 adapter is 1/2mm thick. You remove the OM mount and remove the internal parts. Then carefully trim away the bayonet from the mount. This can be done with a Dremal tool or hacksaw. I dress the mount surface down with sandpaper on a peice of plate glass. I use the self adheive sanding disk used on disk sanders. When removal is done, I use Gorilla glue to glue the M42 mount to the OM mount. Apply a very thin layer and align the mount so the red index marks are close on both mounts. Be careful to position the lens latch slot on the M42 mount, so that it doesn't fall close to the screw hole adjasent to it. Align all of this up dry and mark the two halves with sharpie pen, so you won't have issues when gluing. I clamp the assembly in a vise for a couple hours. Follow the instructions on the glue container. When dry, drill three holes from the inside of the mount, using the existing holes for alignment. A drill press is recomended. Now drill the holes through the M42 mount side for the screw heads, using the three holes in the flange as centers. Clean and debure the assembly thoughly. I tape the holes left by the mount buttons from the outside. I then apply a little JB Weld epoxy to the inside of the mount, to seal the holes. You may have to trim away some of the JB later to allow the mount to seat on the rear of the lens barrel. The next issue is to force the diaphram to manual mode. I used a peice of copper wire to restrain the appetture lever, as seen in my first post of the thread. Install the mount. You can make a nice light baffle from a M42 body cap as seen in my last post. This my also protect the rear element. The lens will focus perfectly from infinity to its closest setting. So far I have converted three a 50mm,24mm and my Cosina 28-7/2.8 zoom. The all work great and cost very little.
Dave
Originally posted by pingflood This is interesting.... I have an OM2 that I rarely use, but always loved the Zuiko glass. The lowly 50/1.8 is one of my all time favorite lenses, and I would love to get it working on my K20D. I DO have a sacrificial K-mount clunker or two sitting around too...
If you just redrill and swap the mount from say a 50/2 Pentax how far off proper infinity focusing will you end up?