Donald Qualls
9-Feb-2005, 15:47
There couldn't readily be a question of orientation unless you removed the glass from the threaded barrels -- otherwise, if it works like other vintage lenses I've had apart, you can't put it back together incorrectly. However...
The Eurynar is a "Doppel Anastigmat" so the front and rear pairs of elements will be mirror images with all elements showing a convex face oriented away from the diaphragm. In some double anastigmats the front and rear element pairs are the same size, in some they're different; if different, the larger diameter pair goes toward the world, the smaller toward the film, but even if symmetrical it's best to get them in the original order, because they may have been corrected in final figuring ("matched") to optimize the performance of the whole lens or each doublet (some double anastigmats can be used as convertibles with the front or rear pair removed). If not cemented and you've lost track of the order, you may have to resort to trial and error to find a combination of front, front inner, rear inner, and rear element that gives the flattest field and best image quality away from the lens axis.
The Eurynar is a "Doppel Anastigmat" so the front and rear pairs of elements will be mirror images with all elements showing a convex face oriented away from the diaphragm. In some double anastigmats the front and rear element pairs are the same size, in some they're different; if different, the larger diameter pair goes toward the world, the smaller toward the film, but even if symmetrical it's best to get them in the original order, because they may have been corrected in final figuring ("matched") to optimize the performance of the whole lens or each doublet (some double anastigmats can be used as convertibles with the front or rear pair removed). If not cemented and you've lost track of the order, you may have to resort to trial and error to find a combination of front, front inner, rear inner, and rear element that gives the flattest field and best image quality away from the lens axis.