Full spectrum photos without modified camera

I have been mapping photos using UVIVF, IR, and Visual into the RGB spectrum. Here's a result that I obtained of a dead leaf:

Despite being a rather mundane subject, and the focus for IR being off, the result has surprised me. All original photos taken with a Fuji XT2 and Rokinon 50mm/1.2.

One of my future plans has been to get a real full spectrum camera, with a quartz lens and buy filters for it. I've also considered a back thinned sensor camera, for more creativity. Once I get the chance, my plan is to do more of this type of photography.

Interesting, but NOT full spectrum. UV induced fluorescence is VERY different to UV imaging. UV images are  quite difficult to capture with digital cameras:

A standard digital camera has no sensitivity to UV.

Most lenses absorb lots of UV, I can't measure any UV with my Panasonic lenses using the spectrometer at work. A few of my older lenses should be usable but only if longer wavelengths are blocked.

The older UV pass filters that block visual wavelengths all leak significant amounts of IR, which shows up on cameras that have been modified to increase their spectral range.

Intense UV light sources are dangerous! We have a source at work that can cause eye damage through UV absorbing glass!

My 'Full spectrum' converted GF2 still has very little UV response due to a thick filter stack. I'm planning on getting my NEX converted at some point for a better try.

Should be a better result if a camera with quartz lens and back thinned sensor with proper filtration. I’m not sure when to expect to be able to get access to such tech. Anyway, thanks for the advice.

SteveInNZ wrote:

I dabbled in a bit of UV photography a while back. This is taken with an unmodified Canon 10D with a B+W/403 filter. It was the only camera I've tried (and I've tried a few) that had any sensitivity at that wavelength and also was very insensitive to the IR that this filter leaks.

Goldmound flower in visible and UV light.

There are a few oddball lenses that are really good for UV without going to the expense of quartz. The easiest to get with reasonable performance are enlarger lenses which have been designed for best performance at the blue end of the spectrum. The focus shift between visible light and UV can be very large. Way more than IR.

The most convenient source of UV light is the Sun. Another cheap option is to use a UV LED through a Woods glass filter like the B+W/403. That will block the IR.

Unless you really want to get right down into UV, you would get better bang for your buck investing in a Baader UV Venus filter, rather than quartz lenses. That filter doesn't have the IR leak that a Woods glass filter does.

I must have another crack at this sometime.

Steve.

The UV LED option, wouldn’t that be considered UV fluorescence?

SteveInNZ wrote:

MacM545 wrote:

The UV LED option, wouldn’t that be considered UV fluorescence?

It's fluorescence if you shine UV light on the target and it emits light at a different wavelength. You'd use a UV blocking filter on the camera and record visible light.

My suggestion is to illuminate the subject with only UV light and record the reflected light. The rational being that UV LEDs and a Woods glass filter are cheaper than an interference filter like the Baader UV.

Steve

Without a woods glass type filter on the lens, there would be a good chance of fluorescence (not all materials fluoresce so some subjects will be free of it).

It's possible to get fluorescence excited by UV & emitted in the NIR (and seen via the filters 'leakage' band) but such a large energy gap would I think be quite unusual (and not well documented as fluorescence spectrometers generally cant measure these conditions).

There are also UV only cases of fluorescence but they generally need more energetic excitation than a UV LED provides, and these probably wouldn't look that different to straight UV reflectance images anyway,

Maybe a great idea