For stationary, tripod-mounted videos (like most of those I’ve created for this book), just about any lens will work for video. However, if you plan to use your DSLR as a family video camera, you should consider how well the lens supports video. Keep in mind these factors:
- Quiet image stabilization. Image stabilization is very useful for handheld video, and the image stabilization systems designed for still shots work remarkably well. However, most of them make an awful clicking sound that the on-camera mic will record. If you need image stabilization that’s not recorded by the on-camera mic, consider the Canon’s STM series of lenses.
- Smooth zooming and focusing. Most lenses don’t focus or zoom all that smoothly; as you turn the dials, they’re a bit jerky. That’s fine for still photos, but it looks awful during video. Look for lenses that have particularly smooth video and focus rings. If you plan to use the on-camera microphone, also look for lenses that are quiet while focusing, such as the Canon STM lenses.
- Motorized zoom. Some mirrorless camera lenses have motorized zooms, which provide much smoother zooms than are possible with a traditional zoom ring. No DSLR lenses have motorized zooms.
- Parfocal (constant focus while zooming). If you plan to zoom while filming, look for parfocal lenses that maintain their focus during zooming. Most consumer lenses need to be re-focused after zooming, which will cause your video to become blurry if you zoom in on a subject. Currently, this limits you to very few lenses: Canon 17-40mm f/4, Canon 16-35mm f/2.8, Canon 70-200mm f/2.8 (without IS), Nikon 17-35mm f/2.8, Nikon 24-70mm f/2.8 AF-S, Nikon 70-200mm f/2.8 VR Mark I, Panasonic Micro Four-Thirds 7-14mm f/4, and Olympus Four-Thirds 11-22mm f/2.8-3.5. Other lenses are not truly parfocal, but they might be close enough for video use, including the Canon 24-105mm L IS (one of the most popular video lenses).
- Breathing. Most photography lenses “breathe,” which means the image zooms slightly when you refocus. To test this, put your camera on a tripod and point it at something with detail, like a bookcase. Manually focus near and then far, and watch the edges of the frame to see if objects are moved in and out of the frame while you refocus. It’s not a problem for amateur videos, but it’s a factor to consider when assessing a lens for serious video production use.
The Canon STM lenses are designed to be used with video, but currently your options are limited to the EF-S 18-55mm f/3.5-5.6 IS STM, the EF-S 18-135mm f/3.5-5.6 IS STM (both for compact DSLRs with the smaller APS-C sensor), the EF-S 55-250 f/4-5.6 IS STM, and the EF 40mm f/2.8 STM (for all Canon DSLRs). These lenses support smooth, silent autofocusing, image stabilization to reduce shakiness in handheld video, and electromagnetic diaphragms to smooth adjustments to the aperture while filming. Note, however, that the 18-135mm is not a parfocal lens, so if you zoom, you’ll also need to refocus.
