One of the joys of using the Micro Four-Thirds system is that the flange distance – ie the distance from the lens mount to the sensor – is only 19.5mm. Most SLR systems designed to fit a moving mirror into this space have flange distances in the 40-50mm range.
This means it is very easy to adapt pretty much any old lens to an M43 body. I have collections of both Minolta/Sony Alpha mount lenses and a goodly number of Minolta MD mount lenses too. Some of these, mostly prime lenses, are very good and can produce images as good as some modern lenses, though the character is often a little different.
Old zooms tend to compare less favourably as aspects of lens design such as computation and coatings were far less advanced.
It is worth noting at this point that some of the Minolta lenses come from a period when they were in collaboration with Leica such that for example my Minolta XE-1 camera shares its design with the Leica R3 and the later XD-7 was also a Leica R4 – though of course the lens mounts were different.
In terms of lenses I have 75-200mm f4.5, 70-210mm f4 and 35-70mm f3.5 zooms that all have Leica branded equivalents.
One of the rumours that I can’t quite get to the bottom of concerns the MD 50mm f2.0 lens. Of the various “nifty fiftys” I own, including f1.4, f1.7 and f2.0 versions, as well as the 45mm f2.0 and an older 55mm f1.7, the MD 50mm f2.0, made in the early 1980s is quite obviously the sharpest and suffers no obvious distortion, yet it was quite cheap – indeed I got mine in mint condition for £10!
It has been suggested that Minolta “borrowed” Leica’s Summicron design for this lens. I can’t confirm the truth or otherwise of this suggestion but it does stand out as a remarkable piece of glass for its age and price!