DxOMark has tested the Canon EOS 70D's live view autofocus system in comparison to the Sony SLT-A77, looking at focus speeds and accuracy in both movie and stills modes. The two cameras offer an intriguing contrast in technologies; the 70D uses Canon's latest 'Dual Pixel AF' on-sensor phase detection, while the A77 employs a separate phase detection AF sensor which receives light via a semi-transparent mirror. Click the link below to see how the two cameras fare in DxOMark's head-to-head testing.
DxOMark review: Canon EOS 70D video AF test: how well does the new sensor-based AF perform?
As always, it's best to take such tests as useful data points that tell part of the story, rather than a definitive final word. DxOMark used the Canon EF 40mm f/2.8 STM on the EOS 70D and the Sony DT 16-50mm f/2.8 OSS SSM on the A-77, which employ very different autofocus systems. The former focuses by moving the whole optical unit back-and-forwards with a linear stepper motor, and we remarked on its slightly pedestrian AF speeds in our recent review. Meanwhile the Sony lens uses an ultrasonic-type motor to drive an internal focus element, which is normally a speedier solution. It's also worth bearing in mind that Canon specifically says it gears the focusing speed down during movie recording to achieve smooth transitions between subjects, as rapid focus jumps can be disconcerting for the viewer.
DxOMark has also completed its three-part article with lens recommendations for the EOS 70D, covering fully 130 options from both Canon itself, and third-party lens makes such as Sigma, Tamron, Tokina and Samyang. Other tests published last week include a sensor review of Pentax's budget K-500 SLR, and reviews of two of Canon's EF-M lenses for its mirrorless EOS M. Click the links below for more:
Click for our preview of the Canon EOS-70D, including initial image quality and focusing tests
Our lens reviews are produced using DxOMark data: click here to see our latest reviews