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Mount converters
Posted: Fri Jul 04, 2008 8:32 pm
by Dr. Harout
Re: Mount converters
Posted: Fri Jul 04, 2008 10:33 pm
by Cogito
Googled a number of relevant words but couldn't find anything for lenses.....
Re: Mount converters
Posted: Sat Jul 05, 2008 11:51 am
by Dr. Harout
I know that the register distance for Alpha mount is 44.5mm and for the Nikon 46.5mm. As for M42 screw mount it's 41.5mm.
So logically, does that mean that when using a Nikon mount lens on Alpha mount we should use a converter with an optical adjustment?

Re: Mount converters
Posted: Sat Jul 05, 2008 4:00 pm
by David Kilpatrick
The Pentax screw register is not 41.5mm - it's 45.46mm, and that 1mm is enough to allow a converter for Alpha. In theory the Nikon lens should be even easier to devise a converter for with an extra full millimetre to play with, but no-one appears even to have made such a converter. If they did, it would be true infinity focus and require no optical element.
David
Re: Mount converters
Posted: Sat Jul 05, 2008 4:10 pm
by Dr. Harout
Thanks David. I will try to find someone to create such a converter, because I have a MTO-1100 f/11 Russian (soviet) made lens and just like a child, I'm impatiently wanting to try it on A700.
Re: Mount converters
Posted: Sat Jul 05, 2008 4:23 pm
by David Kilpatrick
My old friends at SRB Film Services - now renamed rather in an ugly manner, 'SRB-Griturn Ltd' - offer off the shelf adaptors for various lenses on Alpha:
http://www.srb-griturn.com/other-35mm-l ... -337-c.asp
I do not know why they don't offer Nikon, but if you email them, they make very high precision adaptors to order. I once got them to make me a Mamiya Press bayonet mount adaptor on to a Cambo 6 x 9cm view camera front plate, to allow me to use my Mamiya 50mm f6.3 wide angle. They also made Shirley's microscope adaptor, which has not been used for 20 years - though we still have the microscope, a really beautiful Wetzlar-made classic triple lens turret instrument with wooden case from the mid-20th c. They still have the ability to machine adaptors to order, including bayonets.
Here is another page on lens conversions - the MTO is such a well known lens, I am sure they could provide an answer.
http://www.srb-griturn.com/lens-conversions-756-p.asp
Since Shirley is ill with strep throat as a result of Alicante crowds plus Easyjet flights (I just got a slight cold, she got really hit) I might drag the microscope out and fix up the adaptor tube on a digital body. We have never done that. Maybe the A350 with live view - it could be interesting.
David
Re: Mount converters
Posted: Sat Jul 05, 2008 8:42 pm
by Dr. Harout
Oh yes! I think I should find some adaptor for my microscopes too. Would be very interesting in my practice. Thanks.