With digital now the dominant image capture medium, it’s easy to forget that taking pictures with a digital or film camera is essentially the same process–a good thing for those of us who learned our f/stops, shutter speeds, and composition back in the day before pixels were the rage. It’s also good news for those of us with collections of optical glass filters from the film era, and also for savvy shooters that want to take advantage of the unique image control capabilities today’s advanced optical filters can provide. In short, when it comes to filters, some things haven’t changed. Here are six facts to remember about optical filters in the digital age:
1. Film Filters Live! With the exception of color-conversion filters used for shooting tungsten film in daylight and vice-versa, virtually any optical glass filter can be used effectively and provide a range of cool, creative, and special effects when used on a digital camera.
2. Screw ‘Em On, Not Up. The only requirement for using optical filters on a digital camera is that the diameter of the filter be equal to or greater than the front element of the lens you’re using, to avoid corner-darkening vignetting at wide-angle zoom settings. If you’re using one of your 35mm lenses on a compatible digital body,the filters will, of course, screw on directly. If not, get a step-up ring so you will be able to, for example, mount 72mm filters on a lens with a 62mm filter ring.
3. Try It, You’ll Like It. Mount an optical filter on a digital camera, and you can see the filter effect before and immediately after you take the shot. With a digital SLR or electronic viewfinder camera, you can, of course, see the effect right in the viewfinder. With a digital compact, don’t bother with the viewfinder, since the LCD shows what the lens sees. No matter what viewing method you use, be sure to first turn off your camera’s AWB (auto white balance) control—otherwise your camera will; automatically “correct” thus cancelling the desired effect.
4. Real Polarizing. Electronic plug-in filters (which are really mini enhancement programs added to Adobe Photoshop and other image-editing software) are great for many things, but not polarizing. They give you only the effect of polarization. Optical polarizing filters actually polarize the light passing through the lens, minimizing glare on non-metallic surfaces and revealing details obscured by the glare. The effect of an optical polarizing filter is variable, so you can see the effect in the viewfinder or LCD as you turn the front ring. When shopping, make sure you get a circular polarizer—it’ll work properly with any metering and autofocus system.
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Tiffen Circular Polarizer Filter
5.Contrast Control. Optical filters are the best way to reduce the actual brightness ratio of a scene with excessive contrast. The exposure latitude of many digital cameras is in between that of slide and print film, and it may not be possible to recapture lost highlight or shadow detail through image editing. A graduated neutral-density filter will let you get a good overall exposure when the subject’s contrast (brightness) range exceeds your camera’s capabilities to capture both the extreme highlights and shadows present in the actual scene.
6. FX Are Easy.Yes, plug-in software filters can give you all sorts of cool effects, but some—such as star patterns and prismatic effects–are easily done the old-fashioned, optical way. The same goes for many subtle soft-focus effects.
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