Expanding your collection of lens filters is a relatively inexpensive way to expand your creative options. A polarizer reduces glare and adds pop to clouds and skies. A neutral density filter reduces light so you can use slower shutter speeds to add blur to waterfalls and waves. An infrared filter lets you explore the surreal world of invisible light. And a close-up attachment lets you get closer without having to buy an expensive macro lens.
In the ideal world, you’d be able to buy each type of attachment and use it with all of your lenses. But that world doesn’t exist, at least not in this universe. The problem is that lenses often have different-sized threads for screwing filters into place. Some lenses have larger diameters than others, and that means they also have larger filter-thread diameters.
For example, my walk-around zoom lens has 72mm filter threads. My macro lens has a thread size of 62mm. My 50mm prime uses 52mm filters. And my ultra-wide zoom lens uses 77mm filters. So if I want the flexibility to shoot with a neutral density filter on each of the lenses I use most, I need to buy four ND filters—at about $75 apiece.
But there’s an alternative, and it’s the subject of this week’s The Practicing Photographer. Ben Long shows how to choose and use step-up and step-down rings—simple adapters that screw on to a lens and let you attach a filter that wouldn’t otherwise fit.