Understanding aperture

apertures top to bottom : f/1.8, f/1.8, f/1.8, f/10, and f/1.8

Hey guys, last time I talked about shutter speed, as part of a series of posts on how to use your camera in manual mode in order to control your exposure and achieve other effects. Today I want to focus on aperture, and I’m pretty excited. Aperture is my favourite – you’ll see why at the end of this post.

Aperture is the size of the opening in the lens when you’re taking a photo. When you press the shutter of your camera a hole opens up inside your lens which lets light through. Your aperture determines the size of that hole, so the larger the hole the more light gets in (the smaller the hole the less light). Aperture is measured in ‘f-stops’. You would have probably seen something like ‘f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22’ before. Moving from one f-stop to the next either doubles or halves the amount of light going through the lens. At this point I’ll have to mention shutter speed again, as it follows the same principle: a change in shutter speed from one stop to the next also doubles or halves the amount of light getting in. So if you increase one of them (either aperture or shutter speed), and decrease the other one you will still have the same amount of light getting through your lens.

Just a little more tech-stuff before we move on to the really nice effects : Don’t get confused by the f-numbers. A large aperture (when the hole inside your lens is big and lets through lots of light) is represented by a small f-number (e.g. f/2.8). And the other way round: A small aperture (small hole – lets through little light) is given as a large f-number (e.g. f/22).

The biggest impact aperture has on the outcome of your photos is by influencing the depth-of-field. A large aperture results in a shallow depth-of-field, where only a small part of the photo is in focus, and the rest (in front and behind the point of focus) is blurry. A small aperture gives you a large depth-of-field, which means pretty much everything in your photo (from the foreground to the background) is sharp and in focus.

Keeping this in mind aperture has a huge impact on the outcome of a photo. For example small apertures are often used in landscape photography in order to keep most of the landscape sharp, whereas large apertures can be really handy when it comes to portrait photography. When taking a portrait you usually want your subject to be in focus, and avoid anything distracting. By using a large aperture you get a nice blurry background (due to the small depth-of-field). So keep in mind :

large aperture = small depth-of-field = small f-number (e.g. f/2.8)
small aperture = large depth-of-field = large f-number (e.g. f/22)

I love using a large aperture which gives me a nice blurry background, and focuses the attention on the main subject/object. It can also give you a really nice bokeh effect, making your image look dreamy and soft.

The difference that the size of the aperture can make is really obvious – the 5th photo at the top of the post was taken with an aperture of f/1.8, whereas the aperture for the 4th photo was set on f/10 (both photos of basil). You can see the background in the 4th photo is a lot sharper and in focus than in the 5th picture. (Same with the other images included in this post.)

Now that you know how much of an impact aperture can have on the outcome of your photos you should give it a go. Getting out your camera and experimenting is the best way to get your head around the numbers and getting used to the different results. I’d recommend to use your camera in aperture-priority mode (A or AV), so you don’t have to worry about any other settings for now and can entirely focus on aperture.

apertures top to bottom : f/1.8, f/8.0, f/1.8, and f/9.0

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  1. Great job explaining , it's a nice idea of you to share! I love the beautiful images you used to explain as well.

  2. This is extremely valuable information for me. I''m excited to get out and experiment. Thanks Helena

  3. Nice clear explanation - and beautiful photos! Thank you.

  4. What lens did you use for these photos? Was it a 50mm lens with a 1.8 aperture? Great advice.