Tuesday, August 6, 2013

Latest Breakthrough In Lens Technology Delivers New Word To The Lexicon


Students of photography have always had to learn new words - the nature of the subject seems to generate them; bokeh, scheimpflug, and low-pass being examples. Lens makers have added their share, and have used the language shamefully in the effort to make a model name stick in the minds of potential buyers.

Would you know what a Distagon is? Or a Nokton? Or a Summarit? Are they small-vineyard wines? Diseases? Towns in Bohemia?

No - just maker's family names that describe either a lens formulation or an aperture that you can hopefully achieve. If you attach one lens to the front of another by means of a reversing ring or glue, you can get Summicro-Planars and Oresto-Heliars and I can assure you that someone, somewhere will try it. There will be no real purpose for this and no expectation of success and it will look manky and horrible but then so did the the 1979 Nissan...

One of the current rude blasts of the advertiser's trumpet is to alert us to the fact that a lens has an aspherical element in it - to improve the lens by reducing chromatic aberration most likely. A laudable thing, but it needs an explanation - most lenses have a simple curve on either side of their structure - it might be convex or concave as needed and the radius of the curve can vary but it is the same curve fro the entire surface.

Aspherical elements can have a combination of curves on that surface, and can bend light rays so as to plop the red, blue, and green rays at the same spot on the sensor. Of course the path of the light rays through the completed lens is complex and is altered each time it his another glass or air surface but aspherical element can mean a very high degree of resolution indeed.

But what if we are trying to be artistic and haven't a clue how to do it apart from wearing an earring and an exotic haircut? How can we get a lens that will make our career? The answer was surprisingly simple for a number of major lens makers.

The answer was to cut down on the amount of mounting resin that is used to put the raw glass elements onto the lens-grinding machine and to pour a bucket of hot water into the lubricating spray that keeps the grinders moving smoothly over the surfaces being ground. This is put in 4 minutes before the scheduled end of grind. The effect is to slightly soften the blank on the mandrel and let it slide out of position. The grinder therefore puts an series of odd shapes into the glass at the end of the process and as these elements are incorporated into the finished product, artistic effects are produced.

These artistic effects may be somewhat of a surprise to the artist but then surprise has always been a feature of great art. In the case of Edvard Munch I have always been surprised that he was not lynched...

So - what do you look for when you want one of the new lenses?  Look carefully on the box or in the instruction sheet for the words " unsymmetrical element". You will get what you want and what you deserve. Remember Munch...

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