For those looking to improve your photography skills or just beginning to learn about photography, you have to learn the meaning of aperture and how it can improve your photos…

For starters, not every camera and lens can achieve the same f/stops (in case you couldn’t guess, aperture levels are measured as f/[number]), and similar to shutter speed, changing the f/stop does more than just one thing. Have you ever noticed those black blades within your lenses? In optics, an aperture is simply the hole through which light travels. As you can imagine, changing the size of that hole can make a huge difference in the look and feel of your photographs. There’s an exhaustive definition of the topic over at Wikipedia if you’re interested, but we’re assuming you stopped here because you’re just looking for the long and short of it. Here are a few general rules to understanding aperture:
 
- The lower the f/stop, the more light is allowed in.
 
- Exceptionally low f/stops (f/1.2 through f/2, for example) are only found on a handful of lenses, primarily professional DSLR lenses.
 
- Most point-and-shoot cameras only stop as low as f/3.5 (at best), limiting the amount of light you can fetch when shooting in dimly lit scenarios.
 
- You’ll pay dearly for exceptionally low f/stops. A Nikkor 50mm f/1.8 can be found for ~$100; the same lens with an f/1.4 rating (just one step lower) is three times more expensive at ~$300.
 
- Lower f/stops narrow your depth of field; a shot at f/2 will have a very tight focal point, with a tremendously blurred background, whereas a shot at f/14 (as an example) will focus on the foreground and background with essentially no ‘bokeh’ to speak of.
 
Now that you’ve got a grip on that, we’re going to break down the most common uses of aperture when it comes time to compose a shot.
- A lowered f/stop can be artisically chosen if you want to focus in tight on a foreground subject while introducing a silky, beautiful blur (that’s the ‘bokeh’ we mentioned above) around the subject. This is great for focusing on a person with a less-than-exciting backdrop.
 
- A higher f/stop is useful for capturing vast groups, where you want the persons on the edges to be just as sharp and in-focus as the person in the center of the image.
 
- A lower f/stop is very useful for letting more light enter an image during dimly lit or dark situations; this prevents you from having to boost your ISO (and thus, inject noise and grain) or dramatically slow your shutter speed (and thus, potentially introduce unwanted blur from hand-shake).
 
Let’s look at an example of how lowering your f/stop can be beneficial at night and in situations where you want oodles of bokeh surrounding the subject. The image below shows an identical shot at f/1.4 and at f/8, both taken in a dimly lit room with very little ambient light around. Lowering the f/stop allows a tremendous amount of light to flood in, in turn giving us a useful image without resorting to firing a flash. The moral of this story? Lower your f/stop when you’re in dimly lit areas — your images will thank you!
 

Now, let’s look at an example of injecting bokeh into a shot. These two pictures were taken with a f/1.4 (left) and f/16 (right) aperture. You’ll notice the shot on the left has a soft, silky, progressive blur surrounding the focal point. This highlights the subject and simultaneously hides the ho hum background. The f/16 shot has most of the background in focus, effectively destroying your ability to focus only on the foreground subject and disregard the lackluster backdrop. On the flipside, your backdrop is in focus, so if that is your goal for a shot, now you know how to accomplish it. The moral of this story? Lower your f/stop if you want to introduce bokeh, bring out the foreground subject and blur the background; raising the f/stop will help you to focus on a larger image, such as capturing an entire soccer team.
 

What is Aperture? //AuFait Magazine

Article by Dana Murph for Gadling