I recently had the luck to find a classic book on optical production methods at my favorite used book store. It is: _Optical Production Technology_ 2nd edition, (1972) Bristol, Douglas F. Horne, Adam Hilger Ltd This is a fairly recent book and discusses to some degree automatic machines in lens making. I don't know if there is a more recent edition. The first edition of this book was published about 1940 by the same company. The Los Angeles City Public Library has copies of the earlier editions but think there on reference only. I've never seen any for sale. There is little in the literature on practical lens making so anything reasonably authentic is welcome. I have not had a chance to read this book in depth but have scanned over it. Its not perfect: for instance, in a section describing optical glass the author begins by stating that there are two broad catagories, Crown and Flint. He then has a couple of paragraphs on crown glass and the origin of its name. One then expects a little on flint glass but on the next page there is no continuation, it goes on to another subject. To some degree the book is quite British oriented, for instance, in the samples of lens types, which is quite limited, English trade names are given instead of the more accepted generic names and Tessars are not mentioned at all. All this is despite the introduction to the second edition stating that the book had been ammended to account for criticism of the first edition, published a few years earlier. The overall impression is similar to the one I have about Focal press books, that is, that they suffer from lack of editing and proofreading. I think this book was also intended to be a trade school text rather than an academic text, it suffers from this. Nonetheless, there is a good deal of useful information in the book. It confirms that there remains a great deal of hand work in the manufacture of lenses. Lenses are ground and polished on machines which handle many lenses at once but this has been the same for many decades. It is in finishing, cementing where needed and centering that lenses are usually done one at a time. There is some additional material about the manufacture of lenses and optical glass at the canon web site. While there are a lot of automatic machines shown the final assembly of a complex lens appears to be almost all hand work. I will write more when I've had a chance to study this book a bit more. I have not done a web search for it, perhaps its actually not very rare.
-- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org
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