How do you get a crisp clear object in focus with a blurred background?

An example would be a picture of someone outside where they are in crisp, clear focus and everything else in the background is completely out of focus... HELP! Does this have to do with the F Stop setting?How do you get a crisp clear object in focus with a blurred background?
You open the objective of your camera as far as possible and set the distance to the object you want to have a clear focus very exact or even a bit nearer than it is, then the background, if it is not too near behind the object, will be blurred.How do you get a crisp clear object in focus with a blurred background?
F-stop refers to the value of the aperture. The aperture ring is ususally found on the lens, but nowadays, it is in the camera body. When the aperture changes, so does the depth of field. Shallow depth of field is what you are thinking of. Deep depth of field is usually know with landscapes.





The narrower the apeture, the deeper the depth of field will be. The wider the aperture, the more shallow it will become. A wide aperture is needed to get shallow depth of field, which means a blurry background, with crisp focus. This blurred background is called bokeh.





An easy way to explain this, is larger f-stop(f-22) is a very narrow aperture, and a smaller f-stop(f-1.8) is a very wide aperture. of the widest they make. The 50mm 1.2 is wider than a 50mm 1.4, and even more so than a 50mm 1.8.





A usual wide aperture that professionals use is a f-1.4 and f-1.2. An example is the Canon 50mm 1.2. This aperture is one of the widest they make. This means great bokeh and excellent low light capabilities. The 50mm 1.2 is wider than a 50mm 1.4, and much wider than a 50mm 1.8.





Hope this helped.
the small numbers are big apetures - fstops





if you shot at F4 its easier to get exclusion than if you shoot at F22........





the longer the lens the easier it is





200mm its easier than 50mm








a
medium telephoto


set the apeture wide open


focus on the object


the F stop setting or apeture not only controls the amount of light allowed thru the lens, but also alters the depth of focus


the wider the apeture the narrower the depth of focus
Shoot using a medium to long telephoto lens with the aperture wide open.





This techique is called Bokeh.





Link





http://www.kenrockwell.com/tech/bokeh.ht鈥?/a>
here's the short answer: get far away and zoom in as far as possible on your subject.