The E-P1 may look like a compact camera, but it isn't particularly small or lightweight compared to most current digital compacts. It measures 120.5 x 70 x 35mm and weigh 335g body-only, about twice the size and weight a typical compact. However to put it in perspective the Panasonic G1 measures 124 x 83.6 x 45.2mm and weighs 385g body only, while the Canon G10 measures 109.1 x 77.7 x 45.9mm and weighs 350g. It's also considerably smaller and lighter than any current DSLR, which is important because it seeks to duplicate a DSLR's performance and image quality.
The E-P1's specification is certainly more like that of an SLR than a compact. It has a 12.3-megapixel 4/3rds Live MOS sensor with a claimed four stops of image stabilisation and Supersonic Wave Filter self-cleaning mechanism. It has a high speed TruePic V image processor (the E-620 has TruePic III+) and it has an extensive range of manual exposure options for the more experienced photographer. The shutter speeds range from 1/4000th of a second to 30mins in B mode, the sensitivity range is 100 - 6400 ISO in 1/3EV increments, and aperture priority, shutter priority and full manual exposure are available.
The camera's controls are similar to those of an E-system DSLR, although styled rather differently. The main shooting mode dial is partly concealed under the left side of the top plate, while exposure control is adjusted via either the rotary D-pad or the odd roller control on the upper right of the back plate, both of which are quite fiddly to operate smoothly.
Control over the main shooting functions such as image quality, ISO setting, metering and AF mode, white balance and drive/self-timer mode is provided by an on-screen quick menu similar to the ones seen on many of Olympus's compact cameras.
Thankfully Olympus has finally seen the error of its ways and changed its main menu design, and it is a massive improvement. Menu options include fully customisable colour profiles, adjustable tone (gradation) and image aspect ratio. The E-P1 can shoot in 4:3, 16:9, 3:2 and 6:6 formats.
There is a hidden area of the menu which, once activated, gives access to an extensive list of custom functions which make it possible to set the camera up just the way you like it, including customising noise reduction, colour space and some default ISO settings.