Last week I blogged some general tips about how to take better pictures (see that post here), and got some great feedback on a few other 'how to' blog to write! The first subject I'll tackle is the blurry background you see in a lot of pictures, especially professional ones. This is actually a term called bokeh, and photographers everywhere are crazy about it!
My friends at dictionary.com define bokeh as "a Japanese term for the subjective aesthetic quality of out-of-focus-areas of a photographic image." Basically, it's in pictures like these where the subject/person is the only thing in focus, and the rest of the background just falls off.
This is kind of a tricky question, because while you can take great pictures with any model of camera, the amount of bokeh does depend on the camera and lens you have. It is dependent on the f-stop of your camera, which is basically the amount that the lens is open to receive light. The wider the f-stop, the more pronounced the bokeh. Many professional lenses 'open up' to f/1.4 or f/1.2, which gives that nice creaminess in the background.
However, some lenses and some cameras are not able to open up that wide (smaller number = wider opening in this case), and therefore can't produce the same kind of photo. For instance, according to dpreview.com, the iPhone 5s has a maximum f-stop of 2.4. This is pretty wide, but it won't produce the same bokeh as a lens that opens all the way up to 1.4. Of course, there are other factors that play into this, like the quality of your camera and lens, but that's the basic answer.
So...what can you do to achieve better bokeh? The answer is not to spend thousands of dollars on a fancy camera! It is difficult to keep your subject in focus at f/1.4 especially, and not a feat for the faint of heart. What you can do to blur your background is simple - move your subject away from the background. If your subject and background are on the same plane of view, they will both be in focus. But as your background moves further away from your subject, the subject will remain in focus while the background will become more and more out of focus, thus creating the bokeh effect.
I hope that was helpful to you! Let me know if I need to clarify further, and know this does not cover every single aspect of bokeh or f-stop - it's just the basics to help you out! Leave a comment if you have a 'how to' question you want answered. I'll be tackling posing and lighting soon, so stay tuned! Happy shooting!