There is great understanding about what parameters determine photo resolution. This link give a pretty good explanation of the myths and realities regarding this subject. When reading this article be sure to go to the referenced links to get the full picture. The Myth of DPI.
Here is a link to a Depth of Field calculator http://www.dofmaster.com/dofjs.html.
Fool around with it by putting different values in for the variables and it will give you a great feel for how it the depth of field (front and back changes.
Play with it long enough and you will get a good feel for how to set your camera up before taking a shot. Joe Hunt
Fredmiranda.com contains a broad range of information but what I find most useful are the camera and lens reviews. Also they have a great buy and sell section. Check it out and find all the other features. — Joe Hunt