08 Mar 2016 07:04
"Mirrorless" cameras, more specifically the "professional" Interchangeable Lens style sometimes described as "MILC" or, even more accurately, "EVIL" for electronic viewfinder, interchangeable lens, are the latest fad in amateur photography. And perhaps they are "the future": why have a big, fairly noisy mirror and the wide-angle lens design compromises its placement entails when the image sensor can drive the viewfinder continuously? But as things stand they can be just a headache for serious photography.
- The sensor's continuous exposure - most cameras don't cover it even to change lenses, but only momentarily with a mechanical shutter for fast exposures - tends to attract dust. Some don't have ultrasonic cleaners. A DSLR's sensor is normally covered, and its self-cleaning system typically handles what few dust particles do fall on it.
- Battery consumption is excessive. A DSLR's viewfinder takes very little power and its autofocus system doesn't seem to take much. A few extra batteries quickly outweighs a slightly bulkier camera, plus they are costly and inconvenient to swap out of the charger continually.
- Focusing is slow. A reflex viewer generally incorporates a specialized phase-detection AF unit, which works extremely quickly, and the camera continues to predict focus as the mirror swings and the shutter opens. On the other hand, mirrorless cameras typically allow more intuitive focus-point selection with a touchscreen, like a phone: DSLRs tend to have at best a directional pad or a touchscreen which is not easy to use with the camera at one's face. A pressure-sensitive pad or set of buttons that could be triggered by a single, direct touch with the camera at one's face would be better—as would, of course, an update of the Canon EOS 3's eye-controlled autofocus system.
- An eye-level finder allows bracing the camera against the face for better slow exposures.
- Viewfinder lag. Electronic viewfinders often take a significant fraction of a second to update, making action tracking difficult (although SLR cameras can take a little longer to shoot than the best mirrorless.)
- Electronic viewfinders can be hard to see in bright light. On the other hand, they are very flexible.
- Bigger cameras and face bracing tend to best complement the bigger, heavier better lenses.
- A manual rangefinder camera, like a Leica, doesn't suffer from the battery-life problem of a continuously operating sensor, but a rangefinder isn't accurate enough for full performance of fancy lenses wide open.
(Update, 1/2/17: Mirrorless cameras (or, for that matter, awkwardly mirror-laden and bulky DSLRs in Live View mode) do have an important learning advantage: as Thom Hogan reports in "Why are Mirrorless Cameras Necessary," not just instant after-the-fact feedback, with settings recorded, but as-you-go feedback—even true depth of field without the need for a special large-aperture viewing screen. Plus, part of anyone's travel photography can involve handing the camera to a bystander for a self-portrait - they'll understand the "what you see is what you get" of a preview on the back - for which Live View works fine - much more easily than setting dials and focus points. Or a selfie - just the thing for light weight and a flip screen.)