Minolta MC/MD lens on EOS DSLR body: the NEW EOS-MD flange/adapter

Why Minolta Rokkor lens on CANON EOS DSLR ?

Today, many people are wondering if it is worthwhile using old photographic lenses on modern digital cameras. In this page I will try to explain why this choice makes good sense and hopefully raise some interest and curiosity in all the other photographers out there. The current standards of digital photography are now geared to the production and use of only target autofocus lenses for 35mm and in some cases for APS-C format. Manual focus lenses, made with high-quality mechanics and opticals, are still produced by a few manufacturers (Zeiss, Leica, Nikon) but their costs are prohibitive.

So why use objective Minolta MC/MD lenses on a modern DSLR?

There are five main reasons:

1 - QUALITY: Minolta has developed in the past (1965-1985) some wonderful 35mm cameras (like the SRT 101/303, XM/XE/XD/X700) and some wonderful Rokkor lenses to accompany them. Minolta Engineers showed (in 1972-73) some Rokkor lenses (the "MC Rokkor SI 24/2.8" and the "MC Rokkor 16/2.8 fisheye" in particular) as well as the "electronic" XM camera to Leica Engineers. Leica chose Minolta (read this article in PDF) for a partner in developing their "R System". During the '70s Minolta, Leica and Leitz shared their technologies to develop some SLRs like the Leica R3 (Minolta XE), Leica R4 (Minolta XD) as well as some 35mm lenses. Today, for example, you can find lenses like the Elmarit R 24/2.8 in the Leitz catalogue (the original 9/7 optical design of the Minolta MC Rokkor 24mm f2.8 SI) or the AF 16/2.8 fisheye in the Sony catalogue (the original optical design of the Minolta MC Rokkor 16/2.8 fisheye). With the great 11/8 optical design this was another lens that Minolta manufactured in the past for Leitz!

2 - COSTS:

2.1 - about Minolta MC/MD lens: with the advent of the new digital technology, these “precious ones” (prime) lenses are now cheap on the used market. Their prices are ridiculous compared to the corresponding lens in AF mount. Two examples: on ebay it is possible to buy the famous Minolta MC ROKKOR PG 50/1.4 for approximately $30/60, only a “small” fraction compared to the CANON EF 50/1.4 or the NIKON 50/1.4 or SONY AF 50/1.4 ! On ebay it is possible to buy the great Minolta MD 35-70mm f3.5 Macro (the RAW files generated by my EOS 300D show incredible performance !) for $30-50; this is a ridiculous price for a lens "equal to" the Leitz Vario Elmar R 35-70mm f3.5 (also the MD 70-210mm f4 and MD 75-200mm f4.5 are designed by Minolta and sold by Leitz as "Leitz Vario Elmar R 70-210 f4 and Vario Elmar R 75-200mm f4.5 "). Another example: the MC Rokkor 24/2.8 SI that today, usually, sell from less than 100$.

2.2 - about Canon EOS DSLR: some good and inexpensive DSLRs are now (2009) available on the used market like the EOS 300D (6.3 MPixel) or the very good EOS 350D/400D/20D/30D (8.3-10 MPixel). RAW files generated from my EOS 20D with Rokkor lenses show outstanding optical performance from 100 to 800 ISO.

3 - AVAILABILITY: - The market does not offer a DSLR with Minolta MC/MD mount. The solution here is inexpensive, reversible (see Technical details) and compatible with several EOS DSLR bodies.

4 - TECHNICAL CONSIDERATIONS: - From a purely technical point of view the CANON EOS DSLRs are the best cameras for modification.

Three mandatory conditions occur which are necessary and sufficient for adaption:

4.1 - optical condition: the difference between the CANON EF's lens register (44mm) and the Minolta MD's lens register (43.5 mm) is minimal (only 0.5mm) compared to the register difference between lenses by other manufacturers: Sony (44.50mm), Nikon (46.50) and Pentax (45.46mm). Why CANON ? Because Rokkor lens have optical register that is shorter than all other one, so it is better to perform the adaption using the DSLR with the closest register to Minolta MD, i.e. the CANON DSLRs.

4.2 - mechanical condition: The CANON EF bayonet has a larger diameter than the Minolta MC/MD (SR) bayonet.

4.3 - mechanical condition: the base of the CANON EF's mirror box is constructed such that the Minolta MC/MD lens, once mounted on the EOS-MD flange, does not interfere with the EOS mirror movement and with other parts inside the mirabox.

5 - THE FIFTH ELEMENT: - In december 2006 I read two articles about optical physic for 35mm lens. I'm an Engineer as well as a photographer with a large range of Rokkor lens. At the beginning of 2007, in January, I bought a used EOS 300D - and began to think...

... the following image shows the results !