... my technique is to compose the image and focus about a 3rd of the way into the picture ...
... focusing about 1/3 of the way into the scene and using f8 or f11 will do the job in most circumstances as a rough rule of thumb.
I agree with the simple concept of focusing about one third the way into the picture in order to get the maximum depth of field (DOF). It works.
I was taught to focus a 1/3rd into the scene ...
You cant really go wrong though using the focusing one third in method.
Wow. So many people all saying the same thing, and they're all wrong. I'm sorry to have to break it to you, folks, but the old 1/3 - 2/3 rule is an old wives' tale based on an inadequate understanding of the maths of DOF.
A little while ago I had a slow day in the office so I did some calculations. (Well actually
DOFMaster did.) Suppose you have a 55mm lens on a 350D at f/8. The hyperfocal distance is 20m. With the subject at various distances, the DOF is as follows:
* Subject at 1m: DOF from 0.95m to 1.05m (48% in front)
* Subject at 2m: DOF from 1.82m to 2.22m (45% in front)
* Subject at 3m: DOF from 2.61m to 3.52m (43% in front)
* Subject at 5m: DOF from 4m to 6.65m (38% in front)
* Subject at 6.67m: DOF from 5m to 10m (33% in front)
* Subject at 10m: DOF from 6.67m to 20m (25% in front)
* Subject at 15m: DOF from 8.57m to 60.2m (12% in front)
* Subject at 19m: DOF from 9.73m to 395.4m (2% in front)
Note that there is only one point at which the DOF is 1/3 in front of the subject and 2/3 behind the subject, and that is when the subject is at exactly 1/3 of the hyperfocal distance.
Note also that the maximum DOF is achieved when the subject is at the hyperfocal distance.
My recommendation: focus at the hyperfocal distance or just beyond. The trouble with hyperfocal focussing is that, by definition, objects at infinity are right on the limit of acceptable sharpness. However, "acceptable" is a somewhat flexible term and what's acceptably sharp on a computer monitor might not be acceptably sharp on a 36"x24" print. So if there are objects in the scene "at infinity" (i.e. a long way away), then it's probably safest to err on the side of caution by focussing on a point slightly beyond the hyperfocal distance.