RE: test details
First a disclaimer might be in order: I do not have a formal education in Optics, so my test might be incorrect.
I minimally modified a test that is described in a book named “Introduction to Optical Testing” by Joseph M. Geary (pg 15). You can find it at Google books. Mr. Geary shows how to measure the lens transmission, but I added a spectrometer to the test, so the spectral transmission can be measured.
For the collimated light source I used Xenon light, a concave mirror and 50/50 beamspliter. My integration sphere has larger entrance port then one depicted in the book, so I did not need to use a concave mirror to collect light when lens is removed. I used a spectrometer made by Ocean Optics which measures spectrum from 200-1100 nm.
Best,
B.