One mount to rule them all
By Giorgio Zanetti
23 December 2007
Everybody loves SLR: a great system, wide and flexible, that leaves nothing to practicality.
The key word is "system": any brand tries to offer its range of accessories and especially interchangeable lenses, giving an infinite range of choices to photographers. However, at the same time it's also the most limiting factor, because each brand creates, upgrades or extinguish its own system. For technical, economical and competitive reasons there is a crowd of different and incompatible systems, often within the same range of a single company.
But there is an exception to the rule, one mount compatible with several bodies of different companies, eras and nations: it's not science fiction, and indeed it's history.
This little known Graal of photography is the "M42" screw mount.
Modern photographers are accustomed to bayonet mounts: male slots on the lens that locks in the body mount with a fraction of a turn. Instead the M42 relies on a classical and tested screw, 42mm diameter for 1mm of stepping: something any factory can produce very easily. The only mechanical connection between lens and body is a small pin that closes the diaphragm on shooting time, which is not even universally adopted: simple but effective and free of expensive patents and licenses.
The idea was born in the labs of the german Carl Zeiss, and was soon adopted by GDR [east Germany] and USSR manufacturers. The turning point in the 60's, when was adopted by the japanese Pentax [Asahi at the times] and many smaller firms and producers of thirdy part lenses, spreading it all over the world: however, by the mid-'70s the bayonet race started for all producers, as a natural evolution towards advanced features such as autofocus and electrical contacts.
What remains of this era of interoperability and standardness is a wide range of lenses, often of high quality, if not superb: names like Zeiss, Takumar, Vivitar, Fujinon, Jupiter, Mir, Pentacon, Helios, Rollei that are part of the hall of fame of photography, are easily available used and often at very cheap prices. But many of these may exceed the more expensive and modern offerings of today: indeed, much of the fascination that surrounds film photography is certainly due to the yield of these lenses.
The good news is that the M42 diameter is smaller than that of bayonets: consequently it is possible to manufacture adapters that enable most modern and sophisticated digital SLR to mount these superb pieces of glass and metal with a very little money.
The situation may vary from company to company, but it is possible on all the major brands: anyway, taking a look to your favorite forum surely could enlighten you [there are more M42 fans than you can imagine]. Of course, forget autofocus, automatic exposure and multi coatings: Even zooming is a rare luxury in this world.
If you do not know what the diaphragm is... well, you'll discover, like it or not: but then you'll also discover vast seas of creamy bokeh, you'll get ultra-fast glasses and extreme wide-angles for a fraction of the price you'd expect for, and you'll be amazed by shades and tones colors that your 18-55 has never given to you.
In the photos you can see my current lens lineup: a cheapo japanese 135mm, a russian 58mm, an east Germany 30mm...different brands, countries, ages mixed together so easily. Then you can see the adapter that makes the magic: a bare metal ring with female screw inside and male bayonet outside. Finally, a photo of M42 mount itself, in all its low-tech glory!
So what's stopping you for getting your own mighty Carl Zeiss Tessar lens now?
More How To Stories
Thanks for letting us know!
Thanks for voicing your concerns. Rest assured, we take it seriously. We'll look into it and take any appropriate action.
