BRESSER FluoClear filter for fluorescence 67mm slim

Fluorescence is an interesting light phenomenon with numerous nature photography and technical applications. The specimen is illuminated with short wavelength light, usually in the UV to blue range of the spectrum. Depending on the sample, light with longer wavelength is emitted (e.g. green or red). In the past, fluorescence excitation with blue light was the standard, because UV light was not readily available. But the need of a yellow barrier filter to suppress the blue excitation light, would also block some of the fluorescence, especially in the blue and green wavelengths. If you use "black light", i.e. long wavelength UV or violet light, the violet will overlay the wanted fluorescence signal in the blue and also in the red spectrum, which is especially important to view red chlorophyll autofluorescence from plants or algae.

With the FluoClear Filter is is possible, to use an inexpensive UV-A light source (395nm LED torch or wood lamp) to excite strong fluorescence signals. It is easy to get color neutral photos with no need for a manual white balance. This will enable you to document weak fluorescence signal. You can even combine with white light and show the fluorescent object (i.e. insects, coral) in its natural environment.

The filter has numerous applications in UV macrophotography of flowers, insects, corals and much more. It is also useful in biotechnology, materials science, quality control, mineralogy or forensics to examine and document UV active substances. Applications are also numerous for technical consultants and appraisers, new appications include assessments of buildings to look for water damage  and mould. The filter can be used to verify documents, artwork or paper money.

The FluoClear Filter has a 67mm thread and will directly fit to many macro lenses, e.g. the Canon 100mm f/2.8 macro. For other lens threads, inexpensive step-up / step-down adapters are available. The slim housing does not show vignetting even with wide angle lenses.