Since the launch of the Olympus PEN line, using adapted legacy glass has become synonymous with mirrorless cameras. For me personally it was a huge draw because I could use some of the old Olympus and Pentax lenses I had from my college years.
Using the OMD EM5 with legacy lenses is quite simple. Here is my set up.
I use a Novatec adapter. There are cheaper ones, but I have had great luck with the precision and durability of the Novatec adapters.
Here is how I set up my camera after switching the camera to manual focus. I set the movie button to function as magnification button. I set this is custom menu B Button/Dial. It requires 1 push to turn the focus are live, yoy can then reposition the focus area. A second push magnifies the image so you can manually focus. A quick push of the shutter release button and you have full screen and you can recompose if so desired and snap your image.
I also set up manually the focal length so that the EM5's 5 axis image stablization works correctly. I do this in the shooting menu 2/Image Stabilizer and set it manually. If the exact focal length is not there I use the closest.
Olympus uses magnification as opposed to focus peaking to attain critical focus. It is quite easy to do. I've had very good luck with this process although I will be honest, if Olympus could put actual focus peaking on the OMD EM5 I'd be in heaven. Why? Because I think focus peaking is quicker and faster.
Regarding specific camera settings, I shoot on full manual using the lens to stop down the aperture. I like to switch to center weighted metering as most old vintage cameras were center weighted.
- There really is only one issue and that is the chromatic aberration. Since old lenses are not electronically connected, the camera software can't remove any so you need to do all that in post processing. It takes seconds in Adobe lightroom.
- Bokeh. Old glass can have a busy bokeh. For some this will be an issue and for others it will not. It will also depend on the back ground.
- Your image may require some cropping depending on how you like to shoot due to the MFD (minimal focus distance). Many folks have become accustomed to the super short MFD of the new digital lenses.
Here are some images taken with my old Olympus OM lenses on my OMD EM5. The first row are all taken with the lovely Zuiko OM 135mm f2.8 and the second row is with my 50mm f1.8 or 35mm 2.8.