Beginner Photography Tips - Understanding Aperture and Depth of Field

Have you ever wondered why the shot that lookedhave your camera set on "P" or "Tv" thereby having
so good through the viewfinder just doesn't lookit choose the aperture), that aperture may well be
right when you view it later?  Odds are it is becauseset at f 8.  As soon as you press the shutter
you are not in control of your camera, specificallybutton the lens "stops down" to f.8, (which you don't
your aperture.  The aperture is one of the twosee because the mirror has flipped up) and the
options for controlling the exposure.  Aperture andpicture is taken.
depth of field will be the focus of this piece aboutWhen you looked through the lens it is likely that
beginner photography tips.your subject matter was sharp and the background
Aperture refers to the size of the opening throughpleasantly out of focus.  But at F 8 that background
which the light can reach the film or sensor.  Thecomes more into focus and your picture might not
wider the opening, diaphragm or hole, the more thelook nearly as nice.
light and therefore the faster the shutter speed youIf your camera has a depth of field preview button
can use.  But, the aperture has a very importantyou can press that and preview the depth of field
creative aspect to it.  The aperture also plays abefore you shoot. The drawback is that the scene
huge role in the depth of field, the portion of yourthrough the smaller aperture will be correspondingly
image that is in focus, or sharp. darker.  If you don't have that option, you can at
The larger the hole (the lower the number of theleast be aware of depth of field issues and check
aperture), the more shallow your depth of field willyour LCD to see if you captured the look you
be.  The smaller the hole, (the higher the number ofwanted. 
the aperture) the greater your depth of field is.Check your F-stop and see what you are actually
There are other factors that influence the depth ofshooting at, and how that compares to what you are
field, including the focal length of your lens (widerseeing.  It may be that you might actually want
lenses have a greater depth of field) and the zone ofmore depth of field.  Then you would set you f
focus (the closer to infinity you have your focus thestop to as high a number (as small a hole) as possible
greater your depth of field will be).while maintaining a shutter speed you can effectively
When you look through your DSLR you are lookingwork with.
through what is known as a wide-open lens.  That is,Key to getting images that consistently have the
you are seeing through the lens when it is at itslook you want and expect is to understand your
largest hole, or aperture, so that the viewfinder willcamera, how it functions and to be in control of the
be bright.  If you have a 2.8 lens you will be lookingcamera rather than letting the camera be in control
through the lens at f2.8. of you.
If you are not in control of your aperture (if you