Lens Design Information

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I have been shooting 4x5 for about 2 years now and have a 90mm Nikkor f8 and a 150mm f5.6 Fuji W. I am happy with both of these lens and hope to add a 270mm or 300mm in the near future. I have been in the dark long enough concerning lens types. There is always talk on this forum and elsewhere of Tessar, Anastigmat, Plasmat and others,I think. I don't know what any of this means and have had little luck finding any reading on the subject. Any suggestions as to where I might go to find more info on these lens types ?


-- Paul Mongillo (pmongillo@thurston.com), December 13, 2000


One very readable and not overly technical book on lens designs is "A History of the Photographic Lens" by Rudolf Kingslake.

You really don't have to understand the various designs to be a good photographer--the manufacturers have done the work. Your considerations should be things like focal length, speed, coverage, weight, cost, etc. For a 300 mm focal length the first question is whether your camera has enough bellows to use a non-telephoto design. If yes, then cost/weight/coverage point to the Nikkor-M or Fuji-C. If no, then you need to select one of the telephoto designs.

-- Michael Briggs (michaelbriggs@earthlink.net), December 13, 2000.

Thanks Michael for the reading tip. My interest in this subject isn't related to what lens to buy. It is strickly curiosity. Your lens selections are right at the top of my list for a future 300mm purchase.

-- Paul Mongillo (pmongillo@thurston.com), December 13, 2000.

View Camera magazine did an excellent 2 or 3 part series on this that covered basics and a little interesting history. Seems like it was about 4 years ago. Maybe someone with an index could narrow that down.

-- jim galli (jimgalli@sierra.net), December 13, 2000.

A valuable note is found here: http://www.pond.net/~equinox/chat.htm While we all covet the latest and greatest, especially for commercial photography, we also enjoy older, inexpensive lenses that produce wonderful images. I just did some with a lowly Conley 10" Anastigmat c. 1915 that would surprize.

-- David Stein (DFStein@aol.com), December 13, 2000.

I've included a few links that may help - especially the second one.





-- Wayne DeWitt (wdewitt@snip.net), December 13, 2000.

The major differences between a symmetrical plasmat such as a Schneider Symmar or Rodenstock Sironar and a Tessar formula such as a Kodak Commercial Ektar, Schneider Xenar, or Rodenstock Geronar, is the field of coverage which is not going to be important with a 300mm focal length. The plasmats have 72 degrees of coverage and the Tessar types have 56 to 58 degrees of coverage. At a short focal length like 150mm the symmetrical plasmat with 72 degrees of coverage is much more useful because it permits much more in the way of movements. With a 300mm lens the Tessar type lens will permit all the movements you are ever likely to need and it will be less expensive and weigh a bit less. Be sure you have enough bellows extension to use the 300mm. If not you will need a telephoto design, which will permit less movements. All of the Tessar types mentioned above as well as the Ilex Paragon (sometimes also Ilex-Caltar) are good lenses. The Ilex lenses sometimes go for very low prices, but I have found those made in the 1950s and 1960s to be very good. Good luck.

-- Lloyd Frueh (lloydfrueh@yahoo.com), December 21, 2000.

There is nothing wrong in the pursuit of this dream. You will need some tools.

First some intellectual tools. There are some good books on lens design. In particular ones by Warren Smith, Arthur Cox, and Rudolph Kingslake. Some of these books will give you technical data you can use as starting points for a given design. You then need a piece of optical software. There is some freeware (for starters), but the better ones are commercial, made to fit just about every budget, or as complex as you wish.

The major tool that you lack is the experience of an optical shop. This you will need it and it is not impossible to get. There are many types of optical shops. You need the experience of a precision optical shop and I am not speaking of the one that makes your eyeglasses. I recommend arranging a visit to one of the major optical manufacturers and MAKE FRIENDS there. This can be surprisingly easy or difficult. I have twice visited the Celestron factory here in LA but on the third try found they required me to be in a group of 15 or more. As for the actual tools for grinding, polishing etc The friends that you meet along the way will help you with that too. It is amazing what you can pick up by scrounging around on the second and third hand markets and at what prices. I have nothing but encouragement in the pursuit of your dream. And while you're at it remember to have fun.

-- Pat Raymore (patrick.f.raymore@kp.org), December 21, 2000.

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