In our first of occasional articles related to photographic techniques, we look at depth of field. Essentially, the depth of field in an image is the range of distance at which the focal point of the image is still within an acceptable level of focus. This causes the subject to appear in focus and the background appear blurry, or out of focus. Photographers often use this technique to make the subject of an image stand out more. It's a well known and widely used technique, and if you'd like to read more about the technicalities, check out the Wikipedia article on depth of field.

So how do you actually do it? Well, while there are a number of factors, including distance between the subject and background, focal length (how "zoomed in" on the subject you are), the biggest factor is aperture of the lens. The aperture of a lens is the diameter of the hole in the lens that allows the light to pass through and is denoted by what's known as the f-number. The larger the aperture (indicated by a smaller f-number), the less the depth of field. The smaller the aperture, the greater the depth of field. 

Check out the images below which demonstrate this technique, and note the f-number below each image.

                                 f/13                                                                          f/8                                                                       f/2.8

As you can see, the stigma and stamen of the flower remain in focus all the time, while the petals and background progressively get further out of focus as the f-number decreases.

Another image of a butterfly on the same Stargazer Lily was sent out to our email subscribers - you can check it out in the Insects & Spiders gallery. If you haven't signed up for our free email updates, you can do so in the bottom right of every page. By signing up, you'll receive occasional updates and extra stuff from In The Wild Photography via email.

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