I sort of answered my own question when the 200-L arrived. It's in MC mount, which is fine with me. I see from the eazypix.de website that optically, the 200-L is the same as the earlier "apo" model and the 300-L. There are websites which show test results of different Minolta lens and teleconverter combinations. If you are looking at an exotic lens like a 300mm f2 Nikkor and a special teleconverter for it is made by Nikon, you can be sure it will give good results. In most other cases you have to try out the combinations and see how they work. I have OEM teleconverters from Nikon, Canon, Minolta, Pentax, Olympus, Konica, Ricoh, Bronica and Mamiya. I also have independently made teleconverters and some of them are quite good with the right lenses. Some that I like are the Vivitar 2X Macro Focusing Teleconverter, the Panagor Auto Macro Converter, the Tokina RMC, the Kiron Match Mate and some older 7 element models made by Soligor and Komura. In the Minolta MC and MD eras, Minolta did not have many non-mirror telephoto lenses longer than 300mm. People who wanted OEM lenses longer than that usually had Nikon or Canon cameras. This was partly due to the fact that Nikon and Canon made more long lenses and also to the fact that some Nikon and Canon models had interchangeable focusing screens. Using long and slow lenses with cameras which have fixed split image and/or microprism focusing aids is difficult even in good light.