# 5D Mark 3 Auto Focus Question



## infinitex (Sep 5, 2012)

Is there a way to focus on 2 subjects at once? Similar to face detection on my Cell phone.  The camera was set to 61points in the picture below. For those wondering, I passed him in turn 2.


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## Bitter Jeweler (Sep 5, 2012)

No, but you can have the focus encompass two subjects utilizing the appropriate depth of field through control of your aperture.


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## MLeeK (Sep 6, 2012)

You went from a tricycle to a jet airplane. The Jet doesn't perform anything like the tricycle. Now you have to learn about photography. Using 61 focus points or "face detection" will never get you focused on 3 people at once no matter what. Your cell phone has a very tiny sensor in it so your depth of field is great and it's easy to get everything in focus. With your new jet plane the sensor is multitudes larger enabling you to get a shallow depth of field so that you can blur away that unwanted background. Combine that with a wide lens aperture and you might only have the tip of someone's nose in focus. 

Time to start learning about photography!


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## TheBiles (Sep 6, 2012)

I'm fairly certain that "face detection" simply detects the face and focuses on one when you take the photo.  You just see the other one in focus because tiny cell phone sensors give you massive depth of field, and most faces are relatively close to one another in the focal plane.  A camera can ONLY focus at one distance at a time.


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