Frank Mueller , Jun 22, 2003; 09:26 p.m.
The following site lists all Minolta manual focus lenses:
and this is the relevant page with the zoom lenses:
It confirms that there are indeed two MD 100-300mm lenses, one with a fixed maximum aperture of 5.6 and one with a variable maximum aperture of 5.6-6.7. The optical construction appears to be quite different with 13 elements in 10 groups versus 10 elements in 8 groups, respectively.
Unfortunately I have never had a chance to use either of them, and I would say both of them are at least uncommon.
BTW - for this range of focal length I am using a Tokina 100-300mm f/5. It is an older lens of the MC era, ie without the MD lug to fully support the S-mode of XD series cameras and the P-mode of the X-700, but it is of solid construction, has a rotating tripod mount, and is a very solid performer optically - maybe not quite as good as my MD 75-200mm f/4.5, but the latter is an extraordinary lens by any standard. What I am trying to say is that the claim on the above web site that the Minolta MD 100-300mm f/5.6 was made by Tokina is not necessarily derogatory.