How to Check & Correct Your Autofocus: Tips for Fine-Tuning AF to Get Sharper Images

It’s time to sharpen up your pix. Modern DSLRs generally rely on what’s called phase difference autofocusing: basically, a rangefinder scheme updated with new technology. But as I described in the May 2018 issue of Shutterbug, this technology uses a second optical path within the camera, independent of the lens-to-sensor path used to make the photo.

Well, when there are two of anything, they’ll never be identical—excepting protons, electrons, and other elementary particles! Given manufacturing tolerances and the routine punishment you visit on your camera, it’s possible that these two paths are slightly different. Sure, your autofocus oughta focus. But it could be off.

Manufacturers are aware of this problem and often give you a way to “tune” or “microadjust” the autofocus. The adjustment is generally buried among endless camera menus, but a quick web search will tell you if your equipment has this capability.

Click on the image to view a full resolution version of the autofocus test target. Then right click to download it.

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How to Check & Correct Your Autofocus: Tips for Fine-Tuning AF to Get Sharper Images
by Seth Shostak

more at Shutterbug

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