Well, sometimes I need special optics and filters as you may have seen already here. But often they need to be mounted into a frame or filter mount to fit my special lenses. Asking an optical company is often very expensive and they may not even be interested, as often it is just for single units. So what to do then? Ask your optometrist! I have a super good one here, who has always been very helpful, even cutting and precision grinding filter glass or diopter lenses into the special size I need!
My optometrist is https://flair-optik-gastell.de/ and I have always been very happy with him. He even proposed to use special UV cutting coatings on my glasses (>420nm transmitting only), as I work a lot with strong UV LED lights and since then no burning eyes anymore!
So when I do things like these, he was part of that, too...
Gazania Quadriptych of human vision, UV, simulated butterfly and bee vision (left to right, top to bottom):
Rudbeckia Quadriptych of human vision, ultraviolet, simulated bee and butterfly vision (left to right, top to bottom):
Ask your optometrist when you need something for your special photography work, he may be the one who has a solution, and often a much less expensive one!
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos