Originally Posted by
Dave_B
Folks:
In my opinion, any effort of a novice to reproduce the results of thousands of person-years of real world experience in building lenses with some book learning and computer code is likely to be an expensive failure. Lenses are very complicated technology. There are many, many details that spell the difference between a work of art and garbage. For example, the "simple" issue of AR coatings is very complicated with issues like sticking layers, changes in the index of refraction as the layers get deposited, wear layers, chemical stability, dispersion where the index of refraction changes with wavelength, etc. I have designed and built optical systems for a living and one finds that like any manufacturing process, the first few or few hundred or few thousand are crap while one works out the bugs and gets the hundreds of processes locked in and reliable. Which of your colleagues will want the dogs that you made while you were trying to get to the good stuff? The first one of anything complicated costs millions of dollars to build. The right kind of glass with low dispersion and low changes in index with temperature, good mechanical and chemical stability, uniformity of compostion, cutting and polishing, AR layers, low thermal expansion housings, low stress mounts, design of the housings to reduce flare, inside coatings of the housing to appear black, glues, the list of complicated technologies in lens building is quite long.
As an example, think about the recent sad story of a currently active commercial LF lens maker. Clearly they have a small army of very smart people who have spent their entire lives doing this and their firm has done this for a hundred years. They are now recalling lots of very expensive lenses because the glue or the AR coating or the inside paint or some oils on the shutters or something else, who knows what, is causing their lenses to fog. You're going to beat these folks in your spare time? My advice, buy what you want on ebay and take some pictures.
Cheers,
Dave B.
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