Chapter 4: Getting Sharp Focus

For anyone who had the 5D Mark II and waited for the Mark III, one of the top items on the wish list was an upgraded autofocus system. That upgrade came in spades with the 5D Mark III, which has 61 AF points. Fully 41 AF points are cross-type with f/4 or faster lenses. So if you’re shooting action, focus is more precise for even low-contrast subjects, and subject tracking is more reliable.

Canon spared no engineering expense in designing an autofocus system that is versatile and customizable. With all the new features come a plethora of autofocus options. This chapter helps you set up the autofocus system so that it suits your shooting.


With the 5D Mark III, you have plentiful options for setting up autofocus to suit your specific shooting needs. For this image of Deception Falls in Washington state, I used One-shot AF mode with manual AF-point selection. Exposure: ISO 100, f/22, 1.6 seconds, with –1/3-stop of exposure compensation.

Understanding the Autofocus System

It’s important to know that sharp focus ultimately involves three factors: the resolving power of the lens, the resolution of the sensor, and the resolution of the printer. Printing is beyond the scope of this book, and I assume that you’re using high-quality lenses. That leaves one remaining factor — the sensor and internal autofocus system. And it’s safe to say that Canon’s new ...

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