I think I have seen the
Altman lenses you are referring to. They're 6x9, correct?
To answer your question, all lenses are not created equal. You have a few factors at
play. The most obvious of course, is the diameter (in the case of the
Altman lenses listed: 6"). Then you have the
focal length, and this is an important one. 6x9 lenses have a 9"
focal length. 6x12 lenses looks very similar, for example, but are a
bit thinner and have a 12"
focal length. Interchanging the two results in a very ugly and uncontrollable beam.
Then of course you have the difference between plano
convex, aspheric (ala
Source Four, Shakespeare,
etc),
etc but we won't get in to all that. Your Times Square units most likely take two plano
convex lenses arranged "belly-to-belly".
The main thing is to find out the diameter
lens you need as well as the
focal length of your
fixture. If it is 6" diameter, 9"
focal length, the
Altman lens will most likely work. If not, you can buy lenses from other vendors in various focal lengths, but I'll warn you, they are pretty expensive. Not Canon Telephoto
Lens expensive, but $50 a
lens, which can get pricey if you need a bunch. By any chance can you post a photo or model number of the
unit? Most TS lights are square and determining the
lens train by outward appearance can be tricky on those.