Archived posting to the Leica Users Group, 1998/04/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Marc James Small wrote: > > At 12:48 PM 4/26/98 +0000, Chris Bitmead wrote: > >So how come Sigma, Tamron and Tokina have no problems making EOS > >mount lenses? Certainly Canon don't give them any help, legally > >or otherwise. > > They PURCHASE the rights to use the mount from Canon, which then supplies > them with basic engineering drawings. There are a few cases where this has > been done at the request of the OEM, but, normally, it is at the > instigation of the after-market company and is a straight cash deal. _IF_ Canon care enough about the 3rd party lens people, that they are prepared to sell them the right to use the mount, then how come the 3rd party lens people have to reverse engineer the electronics and they don't get it right, resulting in lenses that don't work with later bodies? In other words, I find what you're saying hard to believe because the 3rd party lens makers clearly don't have all the info they need to make the lenses 100% compatible. Anyway, reverse engineering has always been legal. Witness the reverse engineering of the IBM PC Bios that started the whole PC revolution. And reverse engineering a physical mount is trivial in comparison. After all, a bayonet mount is not a new invention that you would think would be patentable. It's just a circle with some prongs sticking out. To take another example, the car manufacturers are always trying to stop 3rd party car parts, which obviously have to fit the same place as the original part. But they have been unable to stop them. - -- Chris Bitmead http://www.ans.com.au/~chrisb mailto:chrisb@ans.com.au