How to set/control focus points, Nikon D3100?
I'm looking for either direct info or a link to an in-depth guide. I recently bought my first dSLR (D3100) and have just started with manual controls.
I already have a vague idea of controlling depth of field, but not quite sure what all the focus settings do and how to control what I'm focused on. While playing around with some of the auto-focus modes (single and continuous-servo AF) I noticed single point area mode would sometimes try to focus but end up blurring everything with a small depth of field, especially on macro shots with blurred background. Then other times (often immediately after not focusing correctly) I would hold down shutter to refocus (without changing anything at all) and it would focus correctly.
How do I get it to focus correctly every time and gain more control over exactly what I want in focus?
Added (1). To clarify I know the manual's definition of the focus settings. But not how they actually work, when to use each one, and how to use them to get exactly what you want in focus and nothing else.
Whenever I have a question/problem such as yours, I read the user's guide
(aka "the manual").
It is amazing just how much I always learn from that.
If that doesn't help (or if I'm interested in a product I don't own), I check the manufacturer's website.
They have descriptions and specs for their gadgets, often have user forums, and the decent manufacturers all let you download the manuals in electronic form (so losing the book is no longer a problem).
Getting the PDF is also useful for those times where the printed book is rather small and useless - the PDFs often have more detailed information.
99% of the time reading the instructions does the trick.
At the same time as studying your manual, you might also want to learn about photography.
Attend a class, read some books, read/watch online tutorials.
The major camera manufacturers (like Canon, Nikon, Olympus etc) all have very useful sections on their website for learning about photography.
http://www.nikonusa.com/...index.page
http://www.olympusamerica.com/...center.asp
http://www.usa.canon.com/...omePageAct
http://photographycourse.net/
Understanding at least the basic principles of photography (as well as being familiar with your camera) will enable you to make the most of your gear, and will make a HUGE difference to your images.