Lately I have been dissatisfied with the ”Aspherical” offerings from the usual Chinese suspects. Their 50mm and 75mm lenses had swirls, bubbles, multi-image with rejects running 4 to 1 good. I am into larger color emitters so p60 platform isn't what was needed. Found Optolife. Ordered several lens 50mm, 52mm & 80mm. The 50 and 80 rock for flashlight use. Dimensional and optical quality is first rate. The 50mm (A293) can be order with AR coating. The 80mm (A142) comes just plain Pyrex. I tried to order the 60mm but it was out of stock. Although I haven't tried any MG lenses the Optolife seem to be a good option.
MG= Melles Griot BTW Optolife is a lens company not a flashlight seller any other lens are uncharted territory.
I trashed one years ago, except bezel and tailcap, so I could actually do it that way w/ what I have now (except the copper!).
I do think I'll end up w/ more lumens OTF w/ precollimation though. I ordered both DX lenses (75 and 78mmm) 6 weeks ago - I've received one 30mm. Ordered from somewhere else, too - lightake maybe? If I get junk from them I'll order this optolife....