This B&W 52mm 093 (87C) Infrared Slim Glass Filter blocks the entire visible spectrum, so to our eyes it looks completely opaque. Unlike the B&W 092 infrared filter, it makes pure infrared photographs possible without the visible red component.
This filter uses B+W's F-Pro mount. Now thinner than their previous mounts, this filter also uses an enhanced retaining ring that holds the filter in place from the rear of the filter. In this way, any chance of damaging the filter from a tight lens hood or additional filter is eliminated.
B&W slim filters are for wide-angle lenses and are 3mm thick. They do not have a front thread
Its transmission only begins to exceed 1% at 800 nm, rising to 88% at 900 nm, and remains that high far beyond the upper limit of sensitization covered by infrared films
This filter is used less frequently in pictorial photography because of the dramatic loss of effective ISO
In the scientific field, materials research and forensics, the limitation to a strictly infrared range is often important