This week, Canon launched the EOS M, making it the last big camera maker to introduce a "mirrorless," interchangeable-lens camera.
This type of camera is much smaller and lighter than the classic pro- and semi-pro digital single lens reflex camera (DLSR). It also takes photos faster and delivers better picture and video quality than compact cameras.
What is a mirrorless camera best for?
Mirrorless cameras are for photographers who are tired of the slow response of traditional compact or "point-and-shoot" cameras and seek improved picture quality but don't want the weight and bulk of a digital SLR.
Who makes them?
With Canon on board, all of the big boys are in, including Fujifilm, Nikon, Olympus, Panasonic, Pentax, Samsung and Sony.
What does "mirrorless" mean?
These cameras lack the "mirror box" found in DSLRs that reflects light coming through the lens into an optical viewfinder. Instead, you frame your image on the LCD screen, as with a compact camera, or sometimes in an electronic viewfinder. This design change dramatically reduces overall size and weight.
How much smaller are they?
Size and weight vary by model, but you can expect up to a 50 percent reduction in heft and bulk for the smallest versions.
What about lenses?
Like DSLRs, mirrorless cameras allow you to attach the right lens to match your photographic vision, such as a 50mm for a classic portrait. The lenses are typically of higher quality than the built-in lenses on compact cameras.
But the selection is smaller. Canon and Nikon, for example, each have more than 60 lenses for their DSLRs. However, the new Canon EOS M will have just two at the outset when it arrives in October. You can buy an adapter to use Canon's DSLR lenses, but that costs an extra $200.
Panasonic has the most lenses for its mirrorless cameras (which it's been selling for years). It will have 17 by the end of this year. The selection of lenses might be a factor in what brand of camera you buy.
How is the image quality?
Every mirrorless camera will deliver better picture and video quality because they have larger imaging sensors than nearly every compact camera.
It’s the golden rule of digital photography: the larger the sensor, the finer the picture and the less digital noise (graininess) when you shoot in low light at higher ISO (sensitivity) settings.
Sensor sizes vary among companies, with the Pentax Q having the smallest, followed by the Nikon 1 series, the Olympus and Panasonic "Micro Four Thirds" technology and finally the SLR-size sensors used by Canon, Fujifilm, other Pentax models, Samsung and Sony.
[See " What Makes a High-Quality camera "]
How fast are they?
Compact cameras usually dawdle at about one frame per second, while mirrorless cameras offer at least 3 fps, rivaling entry-level DSLRs. That will allow you to capture the antics of children, friends and pets. But don’t expect super-sharp images of fast runners or racecars.
What do they cost?
The entry point is around $500 with a basic “kit” lens included (typically a 3x zoom) for a model such as the Olympus PEN E-PM1. Add more megapixels, features and a high-quality lens and you can easily hit $2,000, for example, with the 24-megapixel Sony NEX-7.