One of the reasons I decided to go for a full spectrum mod to my Canon 5dII
was to explore photography in both the UV and I/R
I had a 48mm Baader IR filter handy...which of course does not fit any of my Canon glass.
A quick rat-through my bit and pieces drawer allowed me to add a Takumar 50mm to the Canon body, plus a now unobtanium 48 to 49mm expansion ring
to fit the filter.
So first light (the Woronora Valley...about 60 paces from my front door)