Focus on Photography: Tech Talk (aperture)

I’ve written before about the exposure triangle. The three ‘points’ of the triangle are aperture, shutter speed, and the ISO. This week, I’ll focus on aperture.

Photographers are always talking about Bokeh, the blur in the background; the “aesthetic quality of the blur of the out-of-focus areas of an image”. Bokeh has been defined as "the way the lens renders out-of-focus points of light" {Wikipedia}.  To achieve great bokeh, photographers manipulate the depth of field, usually by changing the aperture of their lens.

The aperture refers to the size of the opening in a lens that lets in the light. It is measured in f-stops. The smaller the f-stop number, the larger the opening. 

Aperture is important because it determines your depth-of-field, or the portion of your photo that is in focus. A wide open aperture (smaller f-stop) gives you a very shallow depth of field, so only a small portion of your photo will be in sharp focus, and everything in front or behind will be out of focus - bokeh. A smaller aperture (larger f-stop) will give you a much greater depth-of-field, so more of your photo will be in focus.  When taking portraits, many photographers prefer a more shallow depth of field, yielding more bokeh in the background, while landscape photographers use a wider depth of field to capture the whole scene in focus. 

I love to shoot at f/1.2; however, a disadvantage of shooting wide open (with a shallow depth of field) is that it’s much more difficult to nail the focus.  I do not recommend shooting wide open with fast moving kiddies!   As always, I love to encourage you to play around and have fun!  Try setting up several objects and take shots at various apertures – see how your depth of field changes at the varying apertures and watch as your background becomes more or less in focus.  As the holidays approach, a very large aperture can be used to capture fun holiday bokeh.  I’m already in the holiday spirit!  In my example below, I used the Look Around template setfrom Jimbo Jambo Designs  and Cozy Christmas kit from Pink Reptile Designs and Baby it's Cold Kit from Valorie Wibbens.