Canon 40D Autofocus


One of the big advantages touted of the Canon 40D is the autofocus. All 9 of the Canon 40D autofocus sensors are cross-type and the center one can do high-precision/diagonal focusing with F/2.8 lens or faster.

While one can get a "feel" for how fast/accurate focus is, it's difficult to measure objectively without specialized equipment. Over the years, I've shot most of Canon's DSLR line (including some limited time with the 1-series), but my day-to-day shooting has been with the Rebel XTi. After a few days, it's clear that the Canon 40D's autofocus is much faster and really locks on. This was especially evident shooting 6-year old Kyle's soccer practice as you can see in the pictures below. I had similar good results from his game that weekend.

These were shot hand-held in the early evening (decent sun) on a 80° day with a Canon 70-300 DO lens. There are two sets of pictures and the animated slide-show below shows the full-frame resized 20% and then the center 40% of the frame (resized in half) - both smart sharpened. The settings for the first set of pictures was 210mm, F/5.6 (fastest that lens will go), ISO 400, and (mostly) 1/1600 second. the second set was 110mm, F/5.6, ISO 400, and (mostly) 1/2000 second. Center Focus point was used and AI Servo mode did a pretty darn decent job of tracking.

A more challenging test of the 40D AI Servo tracking would be a faster moving object such as car racing or bird in flight - the later can be especially difficult given the small relative size of the target. However, based on these pictures, I'm quite happy with the Canon 40D autofocus tracking! ;-)

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Canon 40D Autofocus - Kyle the Soccer Star!

Watch in real time and use the controls to play, step, pause, slow-down, and speed-up the animation.
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Animated JPG




The Autofocus system is pretty darn good ... see if Canon's Live View can do better. Photohounds may also find the High ISO shootout interesting along with the Canon 40D/Rebel XTi comparison.