In late 2008, Panasonic launched the Lumix G1, the first of a new breed: cameras with larger- sized sensors (compared to compact cameras), interchangeable lenses—and no mirror. You may say that the classic rangefinder is such a camera. True, but the usefulness of rangefinder cameras stops in the low telephoto range because the viewfinder crop gets too small; also, because you’re not looking through the lens, parallax can be a problem. Even at wider angles you often need extra viewfinders to cover the angle of view. (Single lens reflex cameras [SLRs] don’t share this problem because they offer a view directly through the lens.) Unfortunately, the mirror is not only a solution—it’s also a major problem.
• Mirror-slap produces noise
• Mirror-slap introduces shake (I consider this one of the major drawbacks of using a mirror)
• Manual focus is not the strength of this system
• Because of the mirror, wide-angle lenses have to be designed differently (as retrofocus lenses) to allow the space for the mirror. This makes them bigger, but it also seems as if it is more difficult to produce top-quality wide-angle lenses.
• The lenses and cameras get more bulky because of the inclusion of the mirror box and retrofocus lenses.