This is the second part of a new series about photography called, “Ten Things All Photo Geeks Must Know.” It is for the more serious amateur photographer who shoots with a digital camera. These ten tips are the basis for a solid foundation in photography. Once you have these skills in your proverbial camera bag you will be able to advance quickly. Some of the posts will apply to film cameras as well but I am writing this series with an aspiring digital photo geek in mind.
Tip Two- What is an Aperture?


An aperture is to your camera lens what your pupil is to your eye. It is the circular opening through which light travels through the lens to the camera’s sensor (or film) to create an image. The opening can be very small (f/22) or very wide (f/2). Apertures are also referred to as “f-stops.” You will see these numbers engraved on the lens barrel– f/22, f/16, f/11, f/8.0, f/5.6, f/4.0, f/2.8, f/2.0, f/1.8 etc. Each of these values represents one time the amount of light either more or less in quantity. In other words, f/16 will let in twice as much light as an aperture opening of f/22. While on the other hand, an aperture of f/4.0 will let in half the amount of light than f/2. It is counterintuitive, but remember that a larger number f-stop (ie. f/16) is actually a smaller aperture or opening.
Depth of Field

Photo Geek Footnote: ISO 400, Shutter Speed 1/200, f/4 with an 85mm lens.
The aperture, or f/stop, can be very small (f/22) or very wide (f/2). Depending on which aperture you choose, you will have either shallow or deep depth of field. F/22 creates deep depth of field and f/2 is perfect if you want shallow depth of field. In the image above I wanted the bride to be tack sharp but I wanted all the commotion around her to be blurry. So I chose a large aperture (f/4) in order to have shallow depth of field. In general photographers use large apertures (a bigger opening) for portraits so that the subject is in focus but the surroundings are less prominent.

Photo Geek Footnote: ISO 320, Shutter Speed 1/160, f/16 with a 50mm lens.
When shooting a landscape or an image in which you want everything to be in focus a small aperture is needed to get deep depth of field. F/11 and above would be great for deep depth of field. This is also handy to use when you are taking a portrait of a large group of people. In the photo above I wanted everything from the trees in the foreground to the mountains in the distance to be in focus. This was also a very bright day so a smaller aperture works better to accommodate the bright light. This was taken in Cres, Croatia this past summer.

Photo Geek Footnote: ISO 1250, Shutter Speed 1/20, f/3.2 with a 50mm lens.
Sometimes you must choose a large aperture (small number) because you are in a low light situation. In another image from Croatia we were out at night and there was an incredibly beautiful full moon above the mountains. I slowed my shutter speed way down to 1/20 of a second, turned my ISO up very fast to 1250 and was able to squeeze out f/3.2. I knew I would have shallow depth of field so I chose to have the boats and people in the foreground remain in focus while the silhouette of the mountains and the moon went soft. I think this gives it more of an oil painting kind of feel.  
If you missed the first part of this series read it HERE.

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Thanks for reading!