The camera's appearance was unique, as it lacked the ubiquitous SLR pentaprism "hump". Instead, a Porro prism system was used; it fitted sideways within the camera, with a sideways-swinging mirror, and located the viewfinder eyepiece to the left (seen from behind) relative to the lens centerline. The body was largely of ABS plastic over a metal frame; the lens mount was metal, and there was a metal covered area on the left top of the camera. This area also contained the onboard flash, which popped up and forward at the touch of a button. The onboard flash popup mechanism is manual. In low light scenarios the flash will not pop up automatically but the photographer must press the button and pop it up before taking the photo.
The E-300 uses Olympus' patented Supersonic Wave Filterdust reduction system to shake dust from the sensor during startup and when requested by the user; this largely eliminates the problem of dust accumulation on the surface of the image sensor.