FL-D: This filter is normally used to
balance fluorescent light and daylight color film. It can also be
employed to create strikingly warm color that is at once both realistic
and warm, and features noticeably brightened highlights.
Tiffen Enhancing Filter: Made of a unique
Didyminium glass, this filter was first developed and marketed by a
chemist, Howard G. Ross. In its current form, it is supplied in
threaded metal mounts in most common millimeter sizes. It can also be
had on special order in almost any size necessary. Essentially a very
sharp cutting filter, it only affects warm colors, especially red. It
seems to have a reduced but still noticeable effect on orange and
yellow as well. This filter has little or no effect on the rest on the
spectrum. When photographing fall scenes, the effect of the enhancing
filter can be and often is spectacular. Its effect is further
strengthened by combining it with a polarizer. Sometimes you will need
to brighten scenes shot on rainy or overcast days. If warm colors
predominate, an enhancing filter will work very well for this purpose.
The filter itself imposes a 11/3 f-stop exposure penalty and, when
combined with a polarizer, the loss grows to an almost prohibitive 22A
Tiffen 812: Essentially a weak warming
filter, the 812 offers just enough warming to turn dull scenes into
bright, more cheerful ones that seem more acceptable to a majority of
viewers. The filter is also useful as it absorbs excess blue in shade.
It is frequently used to add a touch of color to a pale Caucasian face
shot on a cloudy day.
Double polarizers or polarizer/faders:
The unit consists of two polarizers rotating independently but sharing
a common mount. It is very useful to video- or film-makers for
fade-in/out sequences since it can go from minimum polarization to full
black. The filter is sometimes used as a variable neutral density unit.
Stepless variable neutral density filter:
Made up of two N/D filters rather than polarizers, the user dials in
the density reduction by turning the filter in its rotating ring.
Wide-angle neutral density filter: This
is a normal N/D filter except it is graduated with a stronger N/D
effect in the center and decreasing effect toward the edges. It can be
helpful to even out the light fall-off present in extreme wide-angle
lenses from center to edge.
IR transmission filter: Black, visually
opaque filters that only pass IR radiation. There are two types, one to
pass IR above 720nm and the other for wavelengths above 900nm.
UV transmission filter: Unlike
conventional UV filters transmission filters only pass UV radiation.
All visible light is blocked.