Autofocus
Canon describes the EOS 650D’s AF system as ‘hybrid’, which means it uses a combination of phase detection and contrast detection for focusing. This set-up in the 650D is a first for a Canon DSLR, but it is also found in Canon’s new EOS M compact system camera. The CMOS sensor uses dedicated phase-detection points (which cover the majority of the frame), to keep subjects close to focus in live-view mode, and contrast detection is used once the shutter release has been pressed to achieve the final focus. The use of this hybrid system means the camera is the first DSLR from Canon to offer full-time AF during video capture.
The separate phase-detection AF module has nine cross-type AF points as found on the 60D. This is a step up from the nine-point system of the 600D, which features just one cross-type point. In stills capture, there is little difference in the speed of focusing when comparing the 650D’s AF to a dedicated phase-detection system, and the camera matches the 60D in all situations. It may lack a few AF points when compared to the 11-point and 15-point systems of its direct competitors, but all the points used by the 650D are sensitive cross-types, so even in low light the camera latches onto static subjects with relative ease.
Still and video capture are possible in live-view mode. As phase detection is constantly at work to bring into focus the subject within the focus area, subjects are often close to focus already, and a press of the shutter makes the final precise focus with speed.
There are many other situations in which the desired point of focus is not already close, such as when the camera initially starts up or when recomposing a scene. On these occasions the hybrid AF can be sluggish as it hunts for the subject, and sometimes it fails to achieve a successful focus entirely. In this regard, the system is not a patch on the contrast-detection system used by Panasonic in its Lumix G range, for example. However, this type of focusing is extra to the 650D’s phase-detection system, which works just fine.
What I like about the touchscreen is that in single-point AF mode, a touch of the screen selects the desired focus area, with the spot covering approximately 4% of the frame and selectable just about anywhere within it.
In video-recording mode, focusing is smooth, quiet and effective for the minor adjustments that are often required in a continuous AF system. This is obviously a big advantage over a system that does not offer continuous AF at all, and a plus for video users who are well catered for with this camera. For more tricky subjects, tracking and face detection AF are available too.
