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Britsnap Camera Tips #2 Using your Aperture setting

So…there are many attributes needed for good pictures, but I am going to dive right in and talk about Aperture and your Aperture setting on the camera.

The picture below is typical of most Canon model DSLR’s, this is of the most recent T2i. Nikon or Sony cameras will be similar, but seeing as I shoot with a canon, I am going to use Canon images:)

Most of you  probably started using the big green auto button for your pictures. The  green Auto button is good…for giving your camera to a friend to take your pic…and the little picture ‘preset’ buttons…portrait, landscape etc are okay, in great lighting, but severely limit your creative control. So my focus (excuse the funny pun) is to get you to shoot in the AV setting on the dial. For now I am going to ignore the other settings, I will cover them later in another tips section.

So before we move on…let me explain what AV- aperture is:

Aperture – Think of this as to how wide your camera’s pupil is open. The wider it is open (measure in an ‘F’ Number) say for example f/2 only your subject will be in focus and everything else will be blurry (shallow depth of field) and less light is needed to get a well exposed picture.  The Smaller the opening, say f/11 the more of your picture will be in focus, subject, foreground, background, but requiring more light.

It is also important for me to provide some balance and describe attributes of two other terms:

ISO- a useful control, kind of like a ldimmer ight switch, increase the ISO number to allow the camera to get more light, good for poor or low lighting.

Shutter Speed-the faster the shutter speed, the less ‘motion blur’ you will get and the greater your ability to ‘freeze’ action. In protrait photography, generally the higher the sutter speed, the better.

Below is an image of  All three elements,  Shutter Speed (1/8), Aperture(F22) and ISO (100) in your lcd panel. Each can be changed in different settings, however when you are in AV mode, as you increase or decrease the “F” number (using the tumbwheel), the shutterspeed will automatically change. ISO can be controlled seperatley by pressing the ISO buton on top of the camera and adjusting in the LCD screen.

So now we know all that info, lets talk about how to use the AV mode to get great pictures.


So you want your subject in focus and everything else in the background out of focus, blurry. No problem.

To achieve this, lower your “F” number as low as possible, focus on your subject and shoot, making sure that one of the little red focus dots, as you look through the viewfinder is on your subject. In good lighting, you should achieve the desired effect of an in focus subject and out of focus background.

Troubleshooting: The most common mistake here is a picture that is too dark, to change this, you can try to increase your F number, but not too much or you will loose the focus effect you are looking for. If that does not help, adjust your ISO setting. A general rule is that on a sunny day, outdoors your ISO should be 100-200, indoors, 400+. The downside with increasing the ISO much higher than 400 (on most consumer cameras) is you loose detail and your images are not as clean and crisp. So if your pic is too dark, increase the ISO (You can also have your ISO set o AUTO mode)


If you do not want the blurred background effect, or have multple subjecs that you want in focus, increase the F number on the camera. Doing this will increase the ‘range of focus’.  Focus the camera and shoot.

Troubleshooting: you have a mid-range F number, you focused correctly and your subject is blurry. The main cause for this is either camera, subject or hand shake. These elements are reduced by a higher shutter speed. A general rule if using a 18-55mm lens (the main kit lens that most of you have) is to make sure my shutter speed is 1/60 a second or greater. What tends to happen is if your F number is too high, the camera needs more light to expose correctly, and what it normally does is slow the shutterspeed to get the light it needs. A slow shutterspeed will make your subject blurry. So if your images are all blurry, check your ISO, maybe increase it to 400 and check your shutter speed. The way to increase your shutter speed, while in AV mode is to decrease your F number.

So….did it all make sense??? I hope so, this was the forth attempt at this post, I have tried to leave all the camera jargon out of it and just make this as practical as possible. What I would sugest is to get outside, in good light and practice shooting the same subject, or object at different F numbers. Take note of the change in shutter speed as you change the F number in the LCD Screen. Also when reviewing your images, note how much of the background is in focus, relative to the subject at each different F number.

Try it!