Deviating from the common adage that "everything can be fixed in post," optical filters are an essential tool for current-day photographers and cinematographers to correctly balance exposures and achieve successful results at the time of shooting. In spite of the advancements for digitally manipulating imagery post production, filters offer the unique advantage of being able to get a shot right, in-camera. And in many cases, filters allow you to achieve effects and techniques that are simply not possible any other way.
Photograph above by Joel Tjintjelaar
Due to the consistently increasing ISO sensitivities and detail-gathering capabilities of digital cameras, filter design is now more critical than ever. Digital sensors are much more sensitive to a variety of light spectrums, differentiating itself from film capture, which subsequently requires the use of more neutral filtration. One manufacturer in particular, who has recently developed a new multi-coating process for the utmost in color consistency and neutrality, is Formatt-Hitech. Based in the United Kingdom, Formatt-Hitech produces complete ranges of both cinema and photographic filters, in both glass and resin substrates. Additionally, all of the company’s filters are produced in-house, in Aberdare, Wales.
Neutral Density Overview
One arena where Formatt-Hitech focuses much of their attention is in the development of neutral density filters, which are unique in that they are one of the types of filters that cannot be accurately simulated in a digital manner. Neutral density filters, by definition, are filters entirely or partially composed of a color-neutral area of “density,” which allows you to increase your exposure duration. ND filters are most commonly split between two categories: solid ND and graduated ND, with both designs available in different densities. Solid neutral density filters’ surface is completely covered in optical density, which reduces the entire exposure evenly across the image frame. Graduated neutral density filters, on the other hand, are filters where only a portion of the filter has this density and the rest remains clear. These filters are most commonly used to help reduce the exposure of a particularly bright portion of an image, such as a sky, without affecting the exposure of the foreground. Conversely, solid neutral density filters’ ability to reduce the exposure evenly across the frame allows you to alter your exposure in order to blur movement or use wider aperture settings in brighter conditions.
4 x 4" Firecrest IRND 0.3 to 0.9 Filter Kit
Firecrest IRND Filters
Highlighting their most recent technology, Formatt-Hitech has just launched its line of Firecrest IRND filters, or infrared-attenuating neutral density filters. Where Firecrest technology deviates from the norm in regard to all other Formatt-Hitech ND filters is how the density is applied to the filter. In all other varieties of ND filters, the process begins with a resin substrate being dyed to a certain density. For photographic use, this is where the process ended—for cinema use, these resin substrates would then be sandwiched between two plies of glass for greater durability, rigidity, and compatibility with matte boxes. Eliminating the dyeing process, Firecrest IRND filters begin with a Schott Superwite glass substrate, and then a 15-layer multi-coating is applied directly to the glass via a vacuum-formed, hard-coated, electrolytic process. In the words of Formatt-Hitech, this process is “analogous to anodizing on a glass surface.” In practical terms, it affords incredible neutrality; increased anti-reflective and flare reduction properties; and is also water- and scratch resistant.
Beyond the unique process in which the density is applied to the filter substrate, these filters also contextualize themselves in that they are infrared-attenuating neutral density filters. Compared to past, conventional neutral density filters designed for use with film, these IRND filters are specifically designed for use with digital sensors, which are inherently more sensitive to infrared pollution. With this increased sensitivity to IR light comes the likelihood of color shifts and false colors that become more prevalent when recording longer exposures afforded by the neutral density. The IRND makeup of these filters helps to suppress color shifts caused by IR light to produce markedly more color-neutral results.
The Firecrest line is currently available in rectangular cinema standard dimensions—4 x 4", 4 x 5.65", 5 x 5", 5.65 x 5.65", and 6.6 x 6.6"—in densities ranging from the 1-stop ND 0.3 to the 10-stop ND 3.0, a 16-stop ND 4.8 option is available for significantly reducing the amount of light reaching the lens, and soft-edge graduated ND filters are available in 1-5 stop densities. These cinema sizes also differentiate themselves by being 4mm thick, and the Firecrest multi-coating process is, again, sandwiched between two layers of glass for increased strength during handling.
6.6 x 6.6" Firecrest Graduated IRND 0.3 to 1.2 Filter Kit
In regard to still photographic applications, the only currently available rectangular filter is the 16-stop ND 4.8 100 x 100mm filter; however, a full range of options equivalent to the cinema filters will be available by the fall of 2014, with sizes including 67 x 85mm solid and graduated ND, 85 x 85mm solid, 85 x 110mm graduated, 100 x 100mm solid, 100 x 150mm graduated, 165 x 165mm solid, and 165 x 200mm graduated. These photo-intended filters measure just 2mm thick, making them better suited for most photo-type filter holders, and feature the 15-layer Firecrest coating on the outside of the glass for greater anti-reflectance properties. A foam gasket is also featured on this high-density filter's design, to better prevent light spill between the filter and front of the lens.
Furthermore, the 16-stop solid ND filter is also currently available in 72, 77, and 82mm circular screw-in sizes, with more sizes and densities to come this fall, as well. These filters feature the same construction as the 2mm-thick rectangular filters, but are set in 5.5mm-thick stackable SuperSlim aluminum rings. Additionally, 3mm-thick UltraSlim rings will also be available shortly; these will not feature front threads for stacking but will help to lessen the chances of vignetting when used on wide-angle lenses.
77mm Firecrest IRND 4.8 Filter
ProStop IRND, Standard ND, and Variable ND Filters
Prior to the recent announcement of the Firecrest lineup, Formatt-Hitech’s ProStop IRND filters were the company’s flagship neutral density line, and still hold true to claims of infrared attenuation capabilities and high neutrality. In contrast to the Firecrest line, these filters are manufactured with a more conventional dyeing process, where 1.5mm-thick resin substrates take on densities ranging from 0.3 to 3.0 (1 to 10 stops) or 4mm-thick glass substrates are available in 1 to 8-stop densities. The resin filters are unique in regard to IRND filters, in that they are not quite as neutral as their glass counterparts, but are also much more durable to withstand continuous handling. Circular screw-in filters are also available in 67, 72, 77, and 82mm sizes. Like the Firecrest filters, as well, the ProStop IRND line is adept at eliminating infrared contamination from imagery to maintain true colors throughout the range of densities offered.
Joel Tjintjelaar, Samples using ND 16 Stops
Of note in regard to the 85mm and 100mm ProStop IRND filters is that their design incorporates a foam gasket surrounding the edge of the filter which helps to minimize any light leakage between the lens and filter for long exposures.
Additionally, for not-quite-as-discerning situations, Formatt-Hitech also features a full line of standard neutral density filters, which are available in an even more extensive range of sizes and designs, including combination ND filters with 81EF, 85, or 85B color conversion filtration; soft- or hard-edged graduated; blender designs, which spread the density gradient across the entire surface of the filter; and reverse graduated ND filters, which have the strongest amount of density at the center of the filter that tapers off toward one edge.
105mm Combination 85B and Neutral Density (ND) 0.6 Glass Filter
Finally, the last type of ND filters currently produced by Formatt-Hitech is a range of variable neutral density Multistop filters, which are available in circular screw-in sizes from 58mm to 105mm. This style of filter has gained immense popularity over the past few years, due to its ability to save space in a camera bag, since the single filter can be rotated to provide 0.3 to 1.8 densities. They are also especially useful for filmmakers working on location since turning the indexed ring, which offers greater efficiency when making exposure changes, can control the density value. These filters are all constructed from Schott glass and set within aluminum filter rings that measure 5mm larger on the front diameter, to help minimize vignetting.
GoPro Hero3 and Hero3+ Filters
Formatt-Hitech has also recently begun producing a specialty line of filters and holders dedicated to the GoPro Hero3 and Hero3+ action cameras. Matching the rugged design of the cameras themselves, these filters are sold in packs of 5, 10, or 20, and are constructed from durable CR-39 resin for use in trying and inclement conditions. Similarly, the Delrin-constructed filter holders are also sold in packs—of 2, 3, or 5—and are designed to be as lightweight as possible and adhere to the compact form factor of the GoPro units.
Diving Filter Kit for GoPro Hero3+ Camera
The filters themselves measure just 33 x 36mm and are available in clear, circular polarizer, solid 2-stop neutral density, and UV varieties, as well as Pink, Red, Magenta, and Orange underwater color-correction designs. The ND filters, most notably, were specifically designed for the GoPro cameras in order to prevent the rolling shutter effect that is common when filming fast-moving action.
For greater convenience than piecing together a kit à la carte, three separate pre-made bundles are also available that bundle together a range of filters and holders, including the Starter Filter Kit, Elite Filter Kit, and the Diving Filter Kit.
Speaking of filter kits, Formatt-Hitech also offers an array of filter and holder kits designed to make entry easy into working with rectangular filters with your camera system. Often consisting of two to four neutral density filters, plus a compatible filter holder and adapter ring, these kits are sometimes modeled after a professional photographer and poised to help you achieve effects those photographers are best known for. For instance, Colby Brown’s Signature Edition Kits are specifically designed for landscape photography and contain a soft-edge graduated ND filter, reverse grad ND filter, both with 0.6 densities, as well as a 2-stop solid ProStop IRND filter, modular filter holder, an adapter ring for attaching to specific lens sizes, and an exclusive Colby Brown booklet. Also available is a Premium Edition of this kit, which adds a circular polarizer and polarizer adapter ring.
100mm Colby Brown Signature Edition Premier Landscape Filter Kit for 77mm Lens
For the long exposure photographer, Joel Tjintjelaar’s Signature Kits are formed around three different solid ProStop IRND filters (3, 6, and 10-stop densities), and also contain a filter holder, when applicable, and an exclusive booklet. Signature kits, from travel photographers Ken Kaminesky and Elia Locardi, are also due to be released later this year. The Elia Locardi Signature Travel Photography Kit will be best suited for shooting in crowded cities, and will contain 4- and 10-stop solid neutral density filters and a 3-stop soft-edge graduated neutral density filter. The upcoming Kaminesky Signature Edition will be a new Master Kit, and will update the previous Master Kit by making it more specific to contemporary digital photographer's needs. In place of 1-, 2-, and 3-stop ND filters, which are more beneficial to a film workflow, this new kit will feature 3-, 6-, and 10-stop solid ND filters. Additionally, 2- and 3-stop soft-edge grads and a circular polarizer will also be included.
Other kits are also available of different lines of filters, such as solid Firecrest IRND kits, graduated Firecrest IRND kits, and solid ProStop IRND kits, among others.
Hardware and Accessories
A common component in many of the aforementioned kits is a filter holder, of which Formatt-Hitech manufactures three distinct-sized holders: 85mm-, 100mm-, and 165mm-wide. The 85mm- and 100mm-wide Aluminum Modular Holders are convertible holders that can be configured to accept numerous filters at a time depending on your shooting needs. Both are preset to accept up to three filters at once, with the ability to extend or reduce this amount depending on the lens in use. The slots in these holders can also be set to hold either the thinner resin filters or thicker glass filters, too. For attaching either of these holders to your lens, a compatible Adapter Ring must be used, which screws into the front threads of your lens and then uses a bayonet mounting system for attaching the filter holder.
165mm Lucroit Wide Angle 2-Slot Filter Holder
A more specialized filter holder option is the Lucroit 165mm-wide holder, which was originally designed for wide-angle lenses that do not feature front filter threads. Since these lenses are not natively able to accept any kind of filter, Formatt-Hitech developed a unique mounting system that attaches to the barrel of specific lenses and then holds filters large enough so not to vignette with such wide angles of view. Like the other two holders, the Lucroit system is constructed from aluminum, but can only hold up to two filters at a time. Lens-specific adapter rings are required for attaching this holder to the wide-angle lens of your choice, with the ability to also attach to some common thread diameter sizes as well.
Rounding out Formatt-Hitech’s range of hardware and accessory options, they also produce a line of step-up rings and two 6-pocket filter wallets, for 85mm and 100mm filters.
Rounding out Formatt-Hitech’s lineup of filters is a vast assortment of all other types of filters, with options to suit nearly any shooting situation to help you get the shot right in-camera.
Polarizing: For minimizing surface reflections and glare from non-metallic surfaces, Formatt-Hitech offers both circular and linear polarizers in a variety of circular sizes from 37mm to 138mm to 4.5" cinema-type round filters. In addition to reducing reflections on surfaces like glass or water, polarizers also work to enhance the overall saturation of an image and produce a deeper blue sky. All of these polarizers are constructed from Schott optical glass for maintained image quality and set within smooth-rotating aluminum rings.
105mm Circular Polarizer
Color Conversion: Including both circular and rectangular designs, and encompassing all color conversion grades from the warming 81 to the cooling 85, a huge variety of these filters is available. If shooting film or working under especially trying lighting conditions, these filters are definite necessities in order to render accurate color balance. Similar to altering the white balance setting of a digital camera, these filters are commonly used if shooting daylight-balanced film under tungsten lighting or even if just working in especially cool lighting and some added warmth for greater neutrality is required.
Color Correction: A full range of nearly 1,500 different CC filters is available in circular and rectangle sizes, in CC densities from CC05 to CC80, in all additive and subtractive colors to help in balancing for differing lighting conditions. Each of these filters is used to attenuate the opposite color (i.e. a yellow CC filter absorbs blue light) and can be used to achieve proper color balance in difficult or mixed lighting situations.
Black-and-White Contrast: More than 400 different Wratten-standard black-and-white contrast filters are available for adjusting contrast and tonal value transmission when working with black-and-white film. Ranging from the standard yellow 8 filter to the strong red 25 filter, each color filter affects the contrast of a black-and-white image by darkening the color that’s the opposite of the filter's color itself, and lightening colors similar to the filter (i.e. a red filter significantly darkens a blue sky, rendering it nearly black, while a green 13 filter will lighten foliage and bring out more contrast when photographing skin tones).
Graduated and Solid Color Filters: Totaling nearly 6,500 different filter possibilities, both solid color and graduated color filters are available for creatively enhancing the coloration of imagery. Similar to solid neutral density and graduated neutral density filters, these colored filters alter imagery by adding specific colored effects to the lighter portions of imagery. And in specific regard to the graduated color filters, these can be used to add a unique effect to an otherwise blank sky while maintaining neutral coloration in the darker foreground.
Day for Night: A unique filter designed to mimic the look of dusk or moonlight, Day for Night filters are a creative solid-colored filter that imparts a strong bluish quality to imagery. Additionally, these filters also benefit intentional underexposing of an image due to the natural-appearing coloration that is added to the remaining highlights.
72mm Cool Day For Night 1 Filter
Warm2Cool: Playing off the same principal as variable neutral density filters, and even available in kits with the Multistop filters, Warm2Cool filters are variable color filters that allow you to dial in differing amounts of warming or cooling to a scene. Rather than rotate the filter to control the amount of polarization or effective density to add to a scene, these filters change from warm to cool by rotating the front ring in order to add a specific amount of solid coloring to a scene.
Clear and UV: Clear, UV, and Skylight filters are all available, and can be used as general protective filters or to help clear up haze when photographing distant landscapes or at higher altitudes. Clear filters are simple protection for the lens, with no added filtration; UV filters reduce the bluish cast of daylight in addition to serving as a good leave-on-your-lens-at-all-times option; and skylight filters, similarly, reduce overly blue casts and feature a slight pink tint to better cut haze when photographing landscapes and at higher altitudes.
Enhancing: Warm Tone and Skin Tone Enhancing filters do as their names suggest; help to bring out more warmth in naturally warm tones in a clean and effective manner. The Skin Tone Enhancer filters, specifically, offer a slight warm hue, as well as help to reduce overly blue casts in the scene, and help to emphasize earth tones in a scene.
67mm Warm Tone 2 Enhancing Glass Filter
Fluorescent: Both FL-B and FL-D fluorescent corrections filters can be used to help balance fluorescent lighting to either tungsten or daylight-balanced film for cleaner white tones. These filters, which are green or red, respectively, are specifically designed to lessen any greenish casts within a scene, which are notably difficult to correct for using other filtration.
Cross Screen: Commonly referred to as a star effect filter, cross screen filters feature thinly etched lines on the filter’s surface in order to produce a star effect when photographing specular highlights or point light sources. Ranging from just a 2-point star up to an 8-point star, this family of filters differs in how many streaks of light originate from light sources within the scene.
Hot Mirror: Both circular and rectangular hot mirror filters can be used to reduce the effects of infrared contamination when working with cameras that do not feature a built-in IR filter over the imaging sensor. These filters are typically reserved for older or modified digital cameras with weaker IR filters, but can be useful if making long exposures or working near strong sources of infrared, such as a fire or at sunset.
Soft Focus and Diffusion: A vast array of different kinds of softening and diffusion filters can be used to help gain added control over the final appearance of subjects and the quality of lighting. Each of these filters produces a slightly different quality of contrast or softening, with the main objective throughout the series to maintain subject detail and color accuracy. Certain filters help to reduce the highlights and soften the mid-tones while another filter may focus more on adding warmth or a slight coloring in addition to a diffuse overall quality.
4 x 4" Warm Black Movie Mist 1 Filter
Low Contrast: Again, as the name suggests, these filters help to lessen the apparent contrast of an image to prevent highlights and shadows from losing too much detail in harsh lighting conditions. They are most commonly used in video and broadcast applications, and are ideally used in bright, contrast-rich lighting, such as during midday or early afternoon.
I'm curious about the IRND filter. Does it filter out all IR? I'm wondering, would this filter work on a sensor that does not have native IR blocking such as trleaner arrays in scanners?
According to Fomatt-Hitech, the Firecrest IRND filters should completely eliminate infrared energy at around the 700nm mark. As for use with a scanner, I don't know how you would go about that, as there would really be no way to hold the filter over the sensor of the scanner.
Thank you for the great article on the filters. I have cokin filters ND #4 and Polarizing looking to get a #9 filter.
Thank you for this educational and easy to understand article on filters. I have not progressed beyond a circular polarizing and neutral density filter and am now encouraged to do so! Thanks for sharing.