Video tests of the Canon EOS 650D / Rebel T4i's Hybrid autofocus system
Aug 15, 2012 at 19:39 GMT
What improvements has Canon's Hybrid AF system brought to the EOS 650D's usability in live view, and what might this mean for the forthcoming EOS-M mirrorless camera? As a precursor to our imminent 650D/Rebel T4i review, we've published two videos showing how Hybrid AF works, compared both to conventional phase-detection AF and to a contemporary mirrorless rival (in this case the Panasonic DMC-G5). It's a chance see how the 650D performs but also gives an idea of what we can expect from the EOS-M, which uses the same technologies.
For these videos we've used a Canon EOS Rebel T4i with the EF-S 18-135mm f/3.5-5.6 IS STM lens designed specifically for use with the camera's Hybrid AF system. A further explanation of the system can be found by clicking here, but the basic idea is that phase-detection elements on the main sensor help determine the distance of the subject and contrast detection then performs a focus fine-tune, at that distance. The 18-135mm STM's lens' design features a light, internal focus group that can be quickly accelerated and decelerated to suit this autofocus behavior, and uses a stepping motor to allow fast, quiet and precise movement. The EOS-M uses the same technologies and similar designs to offer the same functions.
So, how do they perform?