The third and final setting you need to learn about is the Aperture Size. The other two settings are Shutter Speed and ISO.

Like The Others
I’ve said before that Aperture Size may be the most difficult to grasp of the three, but that is a relative assessment, overall I would have to say that it too is quite simple. Like ISO and Shutter Speed, Aperture Size is just another way of controlling how much light reaches your digital camera’s sensor. And just like the other two, Aperture Size will have its own affect on how your images turn out.

What Else It Does
Besides controlling the light, it also controls the depth of field. The depth of field refers to the amount of space in your image, from front to back, that is in focus. A shallow or small depth of field indicates that only a small amount is in focus, this creates blurred foregrounds and backgrounds, a nice effect if that’s what you are looking for. A large depth of field refers to having a large amount of the scene in focus.  You can capture detail from the foreground all the way to the distant background, if your depth of field is large enough – useful in landscape photography.

Aperture Size Settings
The Aperture Size is indicated by a number preceded by an F, e.g. F/3.5 or F/22, this is called the F stop. An increase in the number, is considered an increase in the F stop.

Setting Aperture Size For Light
The greater your F stop, the smaller your aperture size, and thus the less light you are allowing to hit your sensor. Not surprisingly, the smaller the F stop, the greater the aperture size, and more light will reach your sensor.

That may seem a little confusing at first, and may take awhile to get used to, so in an attempt to boil it down for you:
F stop is greater – less light
F stop is smaller – more light
Example: F/3.5 lets in more light than F/40

So similar to Shutter Speed, the greater the number associated with the setting, the less light you are letting in. Remember, Shutter Speeds under 1 second are fractions, so that a Shutter Speed setting of 60 means 1/60 second.

Setting Aperture Size For Depth Of Field
Another reason to take control of your Aperture Size is that it controls the depth of field. Whereas, you can compensate for the amount of light your aperture size permits with shutter speed or ISO, you can’t compensate for the depth of field. A smaller aperture (greater F stop) gives you a greater depth of field; a bigger aperture (smaller F stop) would give you a smaller depth of field.

Like so:
F stop is greater (small aperture) – greater depth of field
F stop is smaller (large aperture) – shallow depth of field
Example: F/3.5 smaller depth of field than F/40

What To Consider
So when setting Aperture Size, you must consider the amount of light as well as the depth of field. Also, you should remember that you cannot compensate for depth of field, whereas you may compensate for the light with either ISO or Shutter Speed.

Moving On
So, that’s Aperture Size for you. Now you should know how to read your Aperture Settings, and how it affects your images. That’s enough to go out and start shooting in manual. You will learn a lot by just going out and experimenting, especially with a digital camera. The instant feedback you get with the LCD screen is not only very gratifying, but is a great tool to learn by and to shoot with. If you go out and start shooting, or just stay home and shoot some mundane object, concentrating on getting the correct light exposure, you will likely learn a whole lot, and I encourage it.

The next part in the series will start bringing all three elements together for you, giving you a starting place whenever you are shooting manual in any given situation.