The 100mm Firecrest Filter Holder Kit is designed to allow for the convenient use of up to two, separately-available 100mm-wide, 2mm-thick filters along with an included circular polarizer. This kit comes fully assembled and features a holder which has its sides encased within a cover that helps to eliminate stray light, which could have unwanted effects on exposure, from coming in between any installed filters, as well as the filter holder and the lens behind it.
The included aluminum-alloy filter holder is pre-installed with two pairs of plastic filter slots, a configuration that accommodates two rectangular filters. These slots are attached to the filter holder by a total of four screws, which also serve to apply pressure on any filters placed between the slots. Those screws can be loosened or tightened using the included allen wrench to vary the level of grip upon the inserted filters, which can complement the use of graduated filters whose effect can be adjusted to better suit changing lighting conditions or creative demands by sliding them up or down within a filter slot.
The filter holder cover is constructed from a matte black, scratch-resistant plastic that can be pulled in half to allow access to the filter holder. Compatible 100 x 100mm filters can fit entirely within the cover when they are installed on the holder. To permit the use of rectangular graduated filters that are 100mm-wide, but may be longer than 100mm, the ends of each half of the filter holder cover features two caps that can be substituted for two included slotted caps. Those slotted caps allow rectangular graduated filters to be used with minimal stray light even as they extend beyond the dimensions of the cover while it is assembled.
A built-in gasket placed along the front of the filter holder further ensures that stray light does not come between an installed rectangular filter and a connected lens, regardless of which filter holder cover end caps are in place. Use of the filter holder can be easily accomplished by first screwing the included 82mm adapter ring onto a lens with 82mm front filter threads. Step-up rings are included to allow the adapter ring to be used with lenses that have 67mm, 72mm, or 77mm front filter threads; while additional step-up rings are separately available for lenses with 46mm, 52mm, 58mm, or 62mm front filter threads. After being fitted onto the adapter ring, the filter holder's pull-and-release locking lever helps to provide a reliable, yet adjustable connection that allows the holder to be rotated 360°, further benefiting the use of graduated neutral density and other filters that are enhanced by varied positioning.
The 82mm adapter ring also accommodates the included Formatt Hitech 82mm Firecrest UltraSlim Circular Polarizer Filter. When combined with the adapter ring and installed onto a lens with 82mm front filter threads, or adapted to lenses with other front filter thread diameters, the polarizer filter can be rotated to adjust its effect. The combination of the circular polarizer and the adapter ring, plus an optional step-up ring, can also be used with the filter holder with or without its cover installed. In such instances, an external dial on the filter holder allows for the independent rotation of the circular polarizer.