[Nass]

Would anyone happen to know if the 540 and 360 have UV absorbing glass over the flash tube?

Thanks

[Digitalis]

most likely, most modern studio flash units have the same feature.

[Nass]

bugger

[Digitalis]

but that doesn't suggest that the glass is 100% effective at absorbing UV - depending on the manufacturer sometimes quite a lot can sneak through.

[Nass]

Hmmmmmmmmm, need to do a bit more homework I think. I'm hoping to try some reverse lens macro fluorescence shots

[Digitalis]

I'm hoping to try some reverse lens macro fluorescence shots

For that application I would recommend a continuous UV light source* as opposed to using a flash because the amount of UV light from the flash tube gets swamped by the amount of visible light that is produced - and you would end up wearing out/overheating the flash tube that much quicker. Also be aware that SMC coatings and the glass types used in photographic lenses will absorb UV light as well** which will in all probability extend exposure times considerably.

*UV fluorescent lights, UV LED's

**depending on the frequency of light you are using the rule of the thumb is the higher the frequency > the longer the exposure times will be, which is not all that dissimilar to the approach used for IR photography. Lower frequencies > longer exposure times involved.