What is aperture in photography? All pictures ©Al Macphee/MiraclePR
To answer the question, ‘What is aperture in photography?’, you first need to know what your focal plane is. Take your focus point and extend it in a line to either side (not in front or behind). This is your focal plane.
Your aperture setting affects your depth of field, and your depth of field is the amount in front of and behind your focal plane that is actually sharp.
Imagine someone is taking a photograph of me holding a newspaper in front of me. At a wide aperture of f/2.8, focused on the newspaper, the newspaper will be sharp but my head won’t be. If I move the newspaper in line with my face, both would be in focus. However, because faces are thicker than newspapers, my nose, because it’s sticking out nearer to the camera, might be a bit blurred. At f/2.8, you might be lucky and get my nose, depending on how good your optics are, but don’t count on it. Likewise, my ears are behind the focal plane, so they might be a bit out, but anything along that focal plane, like my eyes, will be sharp. Anything in front of my nose, or the cupboard behind me…forget it! This is because at f/2.8, the depth of field is shallow, less than six inches.
Now, lets go to the other extreme. If I set my aperture to f/32 and focus on that same newspaper, my face will be sharp, whether the newspaper is in front, beside or behind my head. Depth of field is higher with a narrow aperture, so you get more in focus.
What is aperture in photography? Some examples:
Bear in mind that each of your lenses will have its own ‘sweet spot’ when it comes to aperture. Sometimes, it’s worth basing your other camera settings around that.
To find out how aperture relates to shutter speed and ISO, see my post on The Exposure Triangle.
Have a burning photography question you would like Al to write about in his next blog post? Email info@miraclepr.com with your request.