Now comes the X-E1, with the same unique sensor and a much lower price tag.

Nikon entered the mirrorless interchangeable-lens marketplace last year with the Nikon 1 J1 and Nikon 1 V1 models, very compact cameras built around the same 10-megapixel CMOS sensor in a new CX format.

Olympus’ first mirrorless interchangeable-lens cameras were inspired by the company’s popular PEN 35mm compact cameras of the 1960s.

Fujifilm made a real splash in 2011 with the X100, a little gem with a great design, a unique hybrid viewfinder, a big APS-C image sensor and a built-in wide-angle lens.

The replacement for Panasonic’s GF3 entry-level "pocket" Micro Four Thirds model, the new GF5 improves on its predecessor in a number of ways, including a higher-resolution LCD, higher ISO capability, more effects filters, an improved grip and additional video capabilities with a built-in stereo microphone.

Pentax does mirrorless a bit differently. After introducing the smallest interchangeable-lens mirrorless model (with the smallest image sensor) in the Q, they followed up with the largest mirrorless model without a built-in eye-level EVF in the K-01.

Samsung’s mirrorless cameras all feature big APS-C image sensors and are available in "mini-DSLR" and "flat" form factors.

The middle model in Samsung’s Wi-Fi NX lineup, the NX210 offers the same 20.3-megapixel image sensor, built-in Wi-Fi capabilities and shooting features as its siblings.

The most compact member of Samsung’s current NX family, the NX1000 shares the 20.3-megapixel image sensor and built-in Wi-Fi capability of the NX20 and NX210, but measures just 4.5×2.5×1.5 inches and weighs just 7.8 ounces.

Taking over from the NEX-C3 as the entry-level model in Sony’s mirrorless line, the NEX-F3 incorporates a big, 16.1-megapixel APS-C HD CMOS sensor that delivers excellent image quality and video. Besides simple operation, features include Auto HDR, Anti-Motion Blur, Sweep Panorama, 3D Sweep Panorama, focus peaking (for easy manual focusing) and 15 in-camera effects.

While those moving up to a mirrorless interchangeable-lens camera from a point-and-shoot are happy to use the LCD monitor as their composing device, some longtime DSLR (and film SLR) users find it awkward.