Autofocus
Focusing has been one of the big sticking points of compact system cameras and any use of contrast-detect-based systems. Panasonic showed the biggest step forward with its Panasonic Lumix DMC-GH2, which finally offered near DSLR-speed focusing, but the latest system in the Olympus Pen E-P3 claims to better even its DSLR cousins.
However, this bold claim has a few caveats. First, it requires the use of the latest MSC lenses, although as this includes the new kit lens it isn’t much of an issue. It also requires you to engage the camera’s full-time AF from the custom menu. This allows the camera to continue to focus even when the shutter is not half-pressed, so in theory your subject could already be focused before you go anywhere near the shutter button – cutting your focusing time down to practically zero.
The full-time AF works quite gently, which makes it ideal for video, but if you are moving to a new subject quickly it might not have caught up by the time you want to shoot so the focusing required by the half-press is still significant. Also, the continuous focusing struggles in low light, which can leave the camera hunting forward and back as you try to lock on.
For a fair comparison, I tried the E-P3 against the mid-consumer range Canon EOS 7D. Under bright conditions (with full-time AF selected and a static scene) there was little between the two.
However, in low-light conditions, especially when switching between close and distant subjects, the Canon EOS 7D was leagues ahead. As compact system cameras go, the autofocus is generally impressive, but it is still no match for a decent phase-detection system.
