New answers tagged lens-design
First, you link to an article about Gaussian Optics which is a specific branch of optics using coherent radiation/light that has nothing to do with conventional photography. That aside, a lens has a "front" and a "back" so there are two of everything since there is one kind of optical point or optical plane for each side of a lens. In other words, the back ...
They are made by Cosina Japan, none of that Zeiss moved this and that. they are made in the same plant Voigtlander lenses are made of and same glass. Difference is in the aesthetics and looks. You want a german made lens then buy a Leica. still made in Germany. With Leica you get what you pay for. Zeiss you still get a great lens but not what they use to be. ...
Disadvantages, well speed and potentially (depending on the distance needed) the TECHART PRO may run out of space making some lenses focus extremities unavailable. Larger heavier lenses may be to heavier for the focus as well. Overall however it's a very interesting concept, with very few real downsides.
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