In recent years, serious attempts have been made to provide the best of both types in a single device. The Four Thirds System builds DSLRs around a smaller sensor than found in other DSLRs (yet one much larger than those found in compact digital cameras). Sigma’s DP series puts a DSLR sensor in a compact body. These methods produced excellent cameras, but each fell short of the ultimate goal: The Four Thirds System cameras weren’t all that much smaller than “full-size” APS-C-format DSLRs, and Sigma’s DP compacts don’t take interchangeable lenses.
Enter the Micro Four Thirds System, which was introduced by Panasonic with the Lumix DMC-G1 in 2008. Featuring a standard-sized Four Thirds System image sensor, the G1 reduced camera size tremendously by replacing the SLR’s bulky mirror box, focusing screen and pentaprism (or pentamirror) finder with a compact, eye-level electronic viewfinder (EVF).
Four Thirds System pioneer Olympus followed with a Micro Four Thirds System model that was even smaller: The PEN E-P1 has a flat design more like a compact camera than a DSLR, eliminating the eye-level EVF (composing is done via the LCD monitor, as with compact digital cameras).
Panasonic answered with a flat model (the Lumix DMC-GF1) and more “mini-DSLR-”format models, Olympus introduced more flat models, and today we have seven Micro Four Thirds System cameras in production. All Micro Four Thirds System cameras accept the full range of Micro Four Thirds System lenses, plus, via adapter, regular Four Thirds System lenses and pretty much any lens for which an adapter is available.
More recently, Samsung introduced the NX10, which puts a larger APS-C-format sensor in a “mini-DSLR” body with a built-in eye-level EVF. The NX10 features a new NX lens mount and accepts new NX-mount lenses, with an adapter for Pentax-mount lenses in the works.
The newest members of the mirrorless, interchangeable-lens club are the most compact yet, despite housing big APS-C-format, 14.2-megapixel Sony Exmor HD CMOS sensors. The Sony NEX-3 and NEX-5 both feature stylish “flat” bodies and a new Sony Alpha E lens mount. Besides a new line of compact Sony E-series lenses, the NEX cameras also can use Sony (and Minolta Maxxum) DSLR lenses via an adapter.
These mirrorless cameras with DSLR-sized sensors are often called EVF cameras (Electronic View Finder) or, more intriguingly, EVIL (Electronic Viewfinder Interchangeable Lens), although not all actually have eye-level electronic viewfinders. All do have full-time Live-View external monitors; Samsung’s NX10 and all Panasonic models except the GF1 have built-in eye-level electronic viewfinders, the Olympus PEN E-P2 and E-P1L accept detachable eye-level electronic viewfinders.
Many DSLR users (especially those with smaller hands) likely will find the “mini-DSLR” models more comfortable to use, while compact camera users will prefer the “flat” form factor.