Home Forums Let’s Talk Photography Back Focus in the 50mm 1.2 and how to correct technique in order to prevent it Reply To: Back Focus in the 50mm 1.2 and how to correct technique in order to prevent it

#4874

Focal length, aperture and distance to subject all affect depth of field.  We know from your post the focal length is 50 mm and aperture is f/1.2.  At 10 feet, depth of field is .86 feet or just over 10 inches.  At 5 feet, depth of field is .21 feet or just over 2 1/2 inches.  I suppose the good news is your 7D has an APS-C sensor so you are apt to be further away from your subject than if you had a full frame body.

Time to get out your tripod and tape measure.  Mount the camera a couple of feet from the floor, level.  Stretch out the tape measure in front of it.  Stand a book beside the tape measure to act as a target.  Set the aperture to f/1.2.  Take shots focusing on the book as you move the book from a couple of feet from the camera, a foot at a time, to about fifteen feet.  Look at the tape measure in your photos, to see the depth of field.  Let us know what you discover.