Must-Have Optical Filters

Digital technology and software have given us enormous control over our images that we didn’t have in the wet darkroom, and they have made photography more playful, too. Look at the popularity of iPhone apps like Instagram, which by now I’m sure you’ve heard Facebook paid a cool $1 billion to acquire. The social web has an insatiable appetite for images, and this, along with the proliferation of camera phones, has introduced a lot of people to photography who otherwise might have only very infrequently approached a camera. We can add quirky special effects, borders and the like, and share our shots instantly.

Polarizers are our number-one must-have filter. They’re indispensable for removing surface glare and reflections, and also produce rich, saturated skies.

This is all a lot of fun with a smartphone, but as a reader of DP, you want to make your best images when you pick up your interchangeable-lens camera. And while we frequently recommend a range of excellent post-capture applications for refining our best shots, don’t forget that when you’re serious about image quality and true creative control, even the best software isn’t a substitute for optical filters.

Why? Software can only manipulate the pixels as they were recorded by your camera’s sensor. If your exposure blew out the details in the highlights or shadows, no algorithmic wizardry can truly re-create it. And though you may enjoy processing your image files, using these optical filters at the time of capture makes your software work easier. Don’t waste 10 minutes fixing what you could have prevented with a bit of extra glass—that time would be better spent taking more photos!

FILTER BASICS

Before we talk about the top filters you should have in your camera bag, it helps to understand some technical aspects of optical filters. First, a general suggestion: Invest in quality glass. Your lens is only as good as its most inferior element—if you use a cheap filter, you’re compromising the quality of your entire optical system.

Pro-Optic Circular Polarizer

Laminated filters are made by sandwiching a colored gel between two layers of glass. The layers are fused together and the filter is cut and ground to size. The potential downside is that the layers may separate over time, allowing air bubbles to form and rendering the filter unusable. This construction also complicates the filter—there are six surfaces that all must be perfectly flat so as not to degrade the optical performance.

The other approach is to add the color dye to the glass while it’s in a molten state so the coloration is perfectly even and actually part of the glass. In theory, this process produces a higher-quality filter, without risk of fading or uneven coloration. And because these filters are a single piece of glass, there are only two surfaces that must be ground completely flat.

Sunpak 8x?Neutral Density

Quality filters usually will have either aluminum or brass rings. There’s something of a debate as to which is superior. Aluminum is lighter, less expensive and absorbs impact better if you should drop—don’t do it—your camera. If you’re using a filter for lens protection, you may weigh in this factor. The argument for brass construction points out that brass is a harder metal and, therefore, more durable and far less likely to bind to your lens. We’ve used filters of both types for many years with no problems.

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