Beginners guide to your camera : The Aperture

by Jonathan | Aug 12, 2009 at 3:36 pm | guides, photography

CameraGuide

The Aperture | The ShutterThe ISO

This guide is directed towards people who know very little about cameras. Maybe you own a small point and shoot but do not know what all the manual settings mean. Or you want to know what the numbers are that flash up right before you take a photograph. This is for you. I plan to talk a little about the aperture in this guide and will talk about the shutter speed and sensitivity in future guides. Expect this is be very basic and nothing ground breaking. I will try and keep everything in plain English and include a lot of pictures.

Camera Modes

There are three basic parts that are set or measured when you take a picture.

  • The aperture or F-Stop
  • The Shutter Speed
  • The Sensitivity or ISO

Some or all of these settings can be determined for you. It all depends on which mode your camera is set in.

ModeDials

Full auto mode will help you pick out the best settings depending on the amount of light that is available. Aperture mode (depicted with an “A” or “Av”) lets you set the aperture size and then picks the best shutter speed. Shutter mode (depicted with an “S” or “Tv”) lets you set the shutter speed and then picks the best aperture. Your camera may also have a Priority Mode (depicted with a “P”). In this mode the camera will pick a combination of shutter speed and aperture size for you, however you are able to select other equal combinations depending on if you need more of one value.

The Aperture or F-Stop

Let’s break the different parts down by starting with the one that confuses the most people, the aperture. In a camera lens the aperture is the device that closes in order to block (or stop) the light from getting into the camera. The aperture does not block all of the light and in some cases does not block much light at all. Consider this when you are outside on a sunny day and there is a lot of light around. It may be too much light. Just like the pupils in your eyes get smaller when you are outside the aperture of the camera gets smaller to manage the amount of light. The aperture is the device or object inside the camera lens. The size of the hole left when the aperture is closed is called the F-Stop. F-Stops are funny things and just like with wire gauges the smaller the number, the larger the hole that is left when the aperture is closed (the more light that is let through) and vise-versa.

Aperture

F-Stops can be expressed in several different ways: f/8, f-8, or 1:8. Also each step on the scale is equal to double or half the amount of light. Example, the opening of F/8 will let in double the amount of light than F/11 and F/4 will let in half the amount of light than F/2.8 (remembering that the smaller number means larger hole and more light). With this in mind you might hear someone saying that a specific camera is quicker or that a lens is quicker. What this normally means is that it has a lower minimum F-Stop value. Not all cameras can obtain every F-Stop value. Quicker just means that you can use a low F-Stop value and thus a higher Shutter Speed. (I will talk about this in the next guide)

You can imagine that if you are shooting photos in a setting with a small amount of light (indoors) you will require a smaller F-Stop number. When out side or while using a flash you will require a larger F-Stop number. The F-Stop can also have an effect on how much a camera or lens costs. It costs more to manufacture a lens that is efficient enough to carry the light clearly to the camera when the aperture is barely closed. This is especially true for zoom or telephoto lenses.

canonfstop

I want to talk quickly about lenses and how they relate to the F-Stop. Not all lenses in point and shoot cameras are equal even though they all fit into very small spaces. Most point and shoot cameras or cheaper removable lenses will have a variable F-Stop. This means that as you zoom the lens in and out the minimum F-Stop will change. As you zoom out the minimum F-stop will increase and as you zoom in the minimum F-Stop will decrease. You should be aware of this when in a setting that requires a low F-Stop number. Sometimes taking a few steps toward you subject can eliminate the need to zoom and giving you a lower F-Stop. Also when you are going to buy and camera you should take a look at the F-Stop. Typically getting a lens with a number around 2 or 2.8 is the best. This will allow you to take “faster” photographs in low light situations.

Please leave your questions or comments. There will be other guides to follow this one about the Shutter Speed and the Sensitivity.