Filter emulation modes and software are awesome but can’t do everything.
It’s not surprising in this digital age that many photographers rely on digital filter software, instead of traditional glass optical filters, to enhance images and achieve a staggering variety of visual effects.
From casual shooters to pros, photographers turn to software systems like Tiffen Dfx or Adobe Photoshop Lightroom 6 in postproduction. Indeed, these filter emulation systems are very impressive in terms of range, cost and flexibility.
However, traditional glass filters that screw into or snap over a camera’s lens belong in every serious shooter’s camera bag. That’s because photographers can use glass filters to do a number of important things they can’t achieve in any other way. And, like interchangeable lenses, they allow shooters to achieve a wide variety of effects. Moreover, glass filters do this simply, predictably, easily and at the moment of exposure, when photographers are actively engaged in the creative process.
Basically, optical filters operate on exactly the same principle that defines DSLR, mirrorless and most digital point-and-shoot cameras; what you see is what you get! When you mount a filter over the lens, you can observe its effect directly in real time on the LCD or in the EVF before you press the shutter release. And when you capture the precise effect you want, it’s an integral part of the original image file; it’s not a layer added in Photoshop or a plug-in filter effect applied in postproduction.
Certainly, many outstanding images were brilliantly enhanced with filter software on a computer. However, there’s something special about creating the final image in-camera at the moment of exposure. This time-honored technique yielded many of the world’s greatest and most memorable images. Optical filters let photographers do just that, and that’s why many of the most creative visual storytellers use them.
Optical Filters for Digital Imaging: Why and How
The CMOS or CCD image sensor in a digital camera responds to light—and to filters—in much the same way as film. Therefore, any filters your customers used back in the day with color film provide virtually the same effects in digital capture. These include polarizing filters; soft-focus and special effects filters; UV protective filters; color-enhancing filters; graduated filters; and warming as well as cooling filters that provide a redder (warmer) or bluer (cooler) color rendition.
In addition, there are color conversion and color compensating filters for shooting daylight-balanced slide film under indoor illumination or vice versa. While they are of more limited use with digital capture, even they provide a useful color balance preview if the all-important AWB rule is followed. That’s because virtually all digital cameras provide auto white balance (AWB) and also offer specific manual settings for daylight, tungsten, overcast and other general lighting conditions.
The AWB Rule: Always Use Manual White Balance Settings with Color Effect Filters!
Get this point across to any digital shooter that’s inexperienced with using optical filters. Whenever using any optical color filter on a DSLR, mirrorless or point-and-shoot camera, never use the AWB setting. It will automatically cancel the color effect of the filter or seriously compromise it. Always set the white balance control to a manual setting that corresponds to the prevailing lighting condition (e.g., daylight) before mounting the filter. That way, the recorded image will look very close to what is seen in the viewfinder.
Essential Filter Types for Digital Shooters
One optical filter that definitely belongs in every digital shooter’s kit is a polarizer. It eliminates reflections and makes colors pop. Examples: The Tiffen HT circular polarizer, which uses proprietary titanium multi-coating for enhanced light transmission, easy cleaning and durability; and the acclaimed B&W Digital Pro circular polarizer from Schneider Kreuznach.
A circular polarizer is preferable to a linear polarizer. That’s because it won’t adversely affect the metering or autofocus performance of DSLR or mirrorless cameras that incorporate beam-splitters in the optical path. That includes virtually every DSLR in current production.
Polarizing filters should be at the top of every photographer’s must-have list, because they have so many practical uses and unique capabilities. A polarizer is a two-piece, variable-control filter that works by selectively transmitting or blocking light waves, depending on their direction of vibration. By turning its front ring and observing the effect in a camera’s viewfinder (or on the LCD), users can eliminate or minimize reflections on many shiny surfaces. These surfaces include water or glass, but not metal or mirrors. As a result, the photographer can see any details, such as the contents of a store window display, that were obscured by reflections or glare.
Note: no plug-in software filter can provide true polarization that will eliminate glare and reveal obscured details.
Polarizers also let users increase overall color saturation for a more vibrant color palette. In addition, they enrich the contrast of clouds to make them stand out against a deep blue sky. Both of these are extremely useful capabilities when shooting landscapes and outdoor scenes.
Protective UV Filters
It makes a lot of sense to protect a camera lens that may cost $500–$2,000 or more with a simple device that’s readily obtainable for a lot less. That’s why so many savvy shooters mount a clear glass or UV filter to protect their pricey lens against dust, moisture, fingerprints (which can etch glass if not removed promptly) and other physical damage.
A selection of these filters include: the Hoya EVO UV filter, which has an antistatic coating to repel dust; the popular Tiffen UV Protector; and the impact-resistant Sigma WR Ceramic Protector.
These filters can remain on a camera at all times, because they have virtually no effect in ordinary picture taking. However, as the UV designation implies, they will absorb ultraviolet radiation that’s invisible to the eyes. UV may show up as a slight bluish tinge in images taken at high altitudes or over water with film or digital cameras. Moreover, none of these filters significantly affect the exposure, and they’re generally available in wide-angle versions.
Graduated ND Filters
Useful for selective contrast control, graduated optical filters are typically half clear and half tinted. Moreover, the area in between provides a graduated density transition (feathered edge), so the effect blends smoothly and the captured scene looks natural.
Using a graduated neutral density (ND) filter is an excellent way to reduce the actual brightness ratio of a scene having an excessive contrast or brightness range. Typically, the image sensor can’t capture both the brightest and darkest areas in a single exposure.
Popular ND filters include the Tiffen Color-Grad ND, which is available in densities of 0.3, 0.6 and 0.9; and the Heliopan Variable Gray ND filter, which provides densities from 0.3–1.8.
Graduated ND filters allow photographers to get a good overall exposure that looks quite natural, without resorting to HDR settings or image stacking. This is achieved by rotating the filter to position its darkest part over the brightest areas of the scene, usually the sky, and its clear area to coincide with the shadow areas, typically the foreground.
In addition, colored graduated filters like the Tiffen Color-Grad Sunrise transform the average sunrise or sunset into something spectacular, without significantly affecting other colors in the scene.
Neutral Density (ND) Filters
Why would you want less light to reach the image sensor? Even at ISO 100, the ambient light level may still be too high to take pictures at a wide aperture to create the shallow depth of field needed for de-emphasizing a distracting background or making a portrait subject pop off a soft background.
Furthermore, ND filters are effective when shooting at a slow shutter speed to emphasize the feeling of motion, such as when photographing a waterfall.
Indeed, some ND filters will do either and sometimes both without affecting color balance or the color accuracy of the image. A sample includes: the Hoya Variable Neutral Density filter that covers a 1.5–9-stop range; and the classic Tiffen Neutral Density filter, which is available in densities of 0.3, 0.6 and 0.9.
Special Effects Filters
The range of special effects possible with optical glass filters is virtually limitless. Moreover, the ability to add a precise, repeatable, predetermined effect by simply screwing or snapping a filter over a lens is a liberating experience for any creative photographer.
Obviously, we can’t possibly detail every type of special effects filter in this limited space. But even the short list is mind-boggling: linear; curvilinear; random patterns; a profusion of starburst and prismatic effects; an extensive range of levels and types of diffusion; mist and fog; and myriad unique, spectacular color effects. Check out the extensive online catalogs of the major filter manufacturers, including Tiffen, B&W, Schneider, Zeiss, Heliopan, Lee, Hoya, Sony, etc., for a comprehensive picture of what’s available.
A Short Selection of Optical Filters
By having a deep knowledge base of optical filters, you are better positioned to serve knowledgeable photo enthusiasts. In addition, a well-selected inventory of essential filters will serve you well with your most creative and loyal repeat customers. Here are five standout products that represent optical filters as necessary imaging tools.
Tiffen Variable Neutral Density (VND)
This filter is perfect for digital shooters; it lets them shoot at wide apertures and/or slow shutter speeds on bright, sunny days and capture compelling pictorial effects. In effect, this Tiffen VND filter adds another control to the camera—a continuously variable ring that lets users control and assess the amount of light coming through the lens.
By turning the filter’s milled front ring, users can reduce the exposure from 2 stops (ND 0.6) to 8 stops (ND 2.4), or anything in between. In addition, a dotted reference scale makes it easy to return to any previously used setting. Although this filter uses polarization to achieve variable ND control, it is not a polarizing filter. However, it is beautifully made and finished, as well as turns very smoothly and precisely. Moreover, it is manufactured using Tiffen’s proprietary ColorCore technology to seal in the actual filter material, ensuring absolute uniformity. 52mm to 82mm, $108.99–$173.99.
Sigma WR Ceramic Protector
Many experienced shooters use a clear or UV filter to protect their precious lenses from dust, sand, scratches and direct physical impact. However, the Sigma WR Ceramic Protector filter takes this protection to a considerably higher level. It employs a super-hard ceramic substrate that combines an impressive 99.7% transmittance value, a hardness greater than chemically strengthened glass and flexibility greater than sapphire crystal.
As a result, this Sigma filter delivers superior shock, scratch and impact resistance, even under adverse conditions. It also features an easy-to-clean, water-repellent, antistatic coating that resists water droplets and smudging. 67mm to 105mm, $93–$315.
This unique, special effects filter from Hoya Japan’s leading filter manufacturer, is designed to capture sharp images in the center of the field with an increasingly soft, pleasing diffusion toward the edges of the frame. It’s made of high-grade optical glass with fine concentric lines etched into its surface.
The lens yields images with a uniquely diffuse look that’s especially useful in portraiture and fine art photography. The filter glass itself is mounted in a durable, lightweight aluminum ring. And its hard anodized finish resists wear and scratches. 43mm to 82mm, $18.90–$39.90.
Tiffen Digital HT Color-Grad ND 0.6
This updated classic image-control filter lets photographers reduce the exposure by 2 stops in selected areas of the frame; for instance, in an expanse of sky or beach. It also features a feathered edge between the density and clear areas to create a natural-looking taper. Upgrades include a low-profile titanium filter ring and Tiffen’s high-transmission Digital HT multi-coating.
In addition, neutral density filters do not affect the overall coloration of the image. And all Tiffen ND filters are manufactured using the company’s proprietary ColorCore process to ensure uniformity. 52mm to 82mm, $81.99–195.99.
B+W XS-Pro HTC Kaesemann Circular Polarizer
Ideal for shooting summer scenic and landscape images, the B&W high-transmission filter from Schneider Kreuznach increases overall color saturation and adds contrast for dramatic skies. It also eliminates unwanted glare from water and glass surfaces.
Using proprietary Kaesemann foils and MRC-nano coating, the filter provides 99.5% light transmission and a filter factor of 2–2.8x. To get the desired effect, photographers rotate the front ring of this two-part filter until they see the effect in the viewfinder or on the LCD monitor. Note: Circular polarizers don’t affect meter or autofocus accuracy when used on today’s TTL-metering DSLRs and mirrorless cameras. 30.5mm to 95mm, $85–$285.