Canon EOS 70D review – Autofocus
As with a number of other features, the EOS 70D borrows its AF system from the flagship Canon APS-C model, the EOS 7D. The AF system consists of 19 points, all of which are the more sensitive cross-type so they should provide faster and more accurate focusing as they work across both a horizontal and vertical axis.
In bright light, I found the autofocus of the EOS 70D to be extremely fast and accurate, not to mention quiet. In fact, when using the EF-S 18-135mm f/3.5-5.6 STM kit lens, there were a few times when, were it not for the audible AF being switched on, I wouldn’t have known that autofocus had taken place.
In lower light, the camera does hunt around a little more, particularly when using a zoom lens with a f/5.6 maximum aperture at longer focal lengths. At f/4 and larger there was no such problem. Focusing in live view using the Dual Pixel CMOS AF system, it still struggled at f/5.6, but was very snappy at larger apertures, although not quite as quick as the camera’s standard phase-detection system. Dual Pixel CMOS AF in live view is certainly a lot faster than the on-sensor phase detection Canon first used in the EOS M compact system camera.
The EOS M has now received a firmware upgrade to significantly improve its focusing speed, and it would seem that Canon has learned a thing or two about on-sensor phase detection over the past year, as the new 20.2-million-pixel Dual Pixel CMOS AF sensor is a marked improvement. Its development will have been expensive, so I would expect to see it in more Canon cameras in the future.
Another new feature is the aforementioned AF mode selection button on the top-plate. When held down, using the control dial allows you to change the AF mode and the points in use while still looking through the viewfinder. This is great for when you have to act quickly, such as when shooting wildlife.
Image: Taken using the 18-135mm f/3.5-5.6 STM kit lens, the 70D resolves a lot of fine detail