With so many people switching to digital, there are some great buys on traditional darkrrom equipment. My question has to do with dating enlarging lenses; how can you tell which models are the newest in each manufacture's line. I have seen many lenses go for both very high and very low prices on the famous auction site, and would like to try to expand my darkroom arsenal. How can I tell if a given lens model is newer or older? I have no idea how to date lenses within any manufacture's line-up. (At least a Nikkor is a Nikkor, not multiple lines of Nikkors.)
Any help shedding some light is appreciated!

age is not a good factor to concider in my opinion. Only quality, while the nikkors were very good, the better schneiders and rodenstocks were fantastic. A great 30 year old enlarging lens is still great. Ansel printed since the depression (1929) and no one complains about his prints.

Bob

You make a very valid point, but the Schneiders and Rodenstocks both come in multiple lines, so the question becomes Which are the better Rodenstocks and Schneiders? I was originally hoping for an answer along the lines of lens A-1 was replaced by A-2 in 19xx, and using the information as a way of keep track of lens improvements.
But any suggestions for lens models to look out for is welcome. I can print up to 4x5, so a set of enlarging lenses for me would probably be a 50mm; 80mm; and 135mm.
Thanks for any suggestions!

Get modern lenses - old lenses are not coated and that does make a difference. You can know what they look like and their names by visiting the manufacturer's web site. As far as serial numbers, there is no difference that I am aware of in the product run - too expensive for manufacturers to retool for a small change in production. Get a six or more element design - the ecomomy line uses a four-element design. APO lenses will let you work at larger apertures and higher magnifications, but I would be hard pressed to see a big difference in the results from them and the standard line.

I have Rodenstock Rodagon and Nikkor EL lenses and they are excellent. I have also used Schnieder. I doubt there is any real difference between the three manufacturers. Some of these lenses have been rebadged by Omega and Bessler and can be gotten for less on ebay because of the name - no difference in optics or design. I am sorry but I can't remember the names exactly, but I think a Bessler HD is a Rodenstock Rodagon.

A 50mm, 80mm, and 135mm is a good set for 35mm, 6x6/6x7, and 4x5 film. For 6x9, a 105mm lens is better. A 150mm is the standard for 4x5, the 135mm is for when your enlarger height limits magnification. There are fewer focal length choices for apochromatic lenses.