Mechanics Vs Electrics

I have been idly turning over some old film camera lenses – Fed, Nikon, and Yashica – and thinking about the lens mounts they carry.

The Yashica has the old M42 screw mount made popular by Praktica and Pentax. It is literally a screw thread with a small push-pin at the lowest point that actuates the automatic aperture. It is basic but amazing in its own way – amazing in that it has been cut with enough precision of both register the light rays back on the film, and present the lens right way up and in the exact centre position every time. It seems to be reasonably resistant to wear.

The Fed is an even simpler version of the screw mount – the Leica L39 size. No actuator because there is no auto diaphragm. Being Soviet, it is cheap material and will wear eventually, but the lens itself has no hard infinity stop so this will likely dissolve any problem. If it was the proper Leica screw it would not wear enough to be troublesome.

The Nikon is a bayonet, and well done in stainless steel. There are a number of protruding electrical contacts, though, and an actuator bar that needs to be undamaged and free-moving to allow the thing to stop down. It has rather a small throat, which may make design work problematical for future lenses.

None of them are perfect, but they all served a need at the time. And they all have been superseded by later Canon, Fujifilm, and Olympus mounts…not to forget Sony.

Mind you, these firms have chopped and changed somewhat. We all remember the Canon mount changes that went from simple bayonet with locking collar to modified collar and then to straight EOS bayonet mount. It damned generations of Canon users to change lenses once they contemplated digital cameras and led to no end of confusion in the secondhand section of the camera shop. At least Canon did a smart thing in opting for a larger diameter throat on the EOS cameras and a purely electric interface. It will make future lens design so much easier.

Likewise kudos to Fujifilm for their bayonet. Apart from the fact that their lenses need a tactile dot to let the user know how it is oriented in the dark, the mount is near perfect. No sticky-out bits to catch on fabrics as you handle them and a decent diameter for growth.

Olympus and Panasonic also have a good clean mount but they are going to get into the same corner as Nikon eventually – it is a small throat. Granted tit is a small sensor and small camera, but somewhere there is a lens designer that needs more room in the back for the final element of his masterpiece and he is going to have to make compromises because of this.

Idle speculation, but I wonder if there have been any lens system designs that have tried to rely on magnets to faasten the lens to the body? In todays samarium magnet field it might be possible. And it is just a silly enough idea to appeal to the Russians or Hasselblad.

I am philosophical about the changes in photography. New is not necessarily better than old, but that does not stop some new from being better. The trick is to find out if it is – for you – without spending all your eating money.

Feature Image: Plastic packaging from a roll of kitchen paper. Will become the foundation of a lens hood for a non-standard lens. Hand me the gaffer tape and the matt board…

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