Tips and tutorials

Aperture, DOF & those cool blurry backgrounds

Slip, slop, slap.     This funky shirt is from Sick on

Me and my long suffering assistant, Tierney

Me and my long suffering assistant, Tierney. He doesn’t do much.

Hey there! Time for some more camera tips. Our model today is a very funky, pristine Silverette typewriter (another wonderful find from Nanna’s garage).

Please note that this article is aimed at beginner to intermediate camera users, especially those with the options to change settings on their cameras. For this tutorial I used my Nikon D90 DSLR with my 50mm f1.8 prime lens set at 400iso.

sundew bokeh

Sundew – photographed with 60mm macro lens

You’ve probably seen those photos whilst surfing around on Etsy or looking at Redbubble, Flickr etc. Those pretty ones with the sparkly, blurry backgrounds, so light and airy and peaceful. Or the ones shot with coloured lights in the background that just twinkle

This effect is caused by the aperture of the lens and is generally referred to as bokeh or a shallow depth of field (DOF). The shape of this bokeh is a result of the shape of the shutter blades. You can experiment in changing this by putting a black cardboard cutout over your lens…more on that in a later post. Sites like Wikipedia go into great depth about bokeh and circles of confusion, but I’ll try to keep things simple.


There’s going to be a funky version of this on Redbubble soon

Essentially, the more light you let through your lens, the blurrier the background will be. The amount of light let through the lens is controlled by the aperture. If you have a camera with manual settings, this is what the A stands for. When you set your camera to A, you control the depth of field (DOF) and the camera will choose a suitable shutter speed to let you get a good exposure. Sometimes you will need a tripod for this, it all depends on how steady you can hold a camera. I usually don’t like to go under 1/60th of a second whilst hand holding the camera and that varies depending on how long my lens is, but I did today for the purposes of this tutorial…and the fact I broke my tripod.

In photography, things are a little back to front. When we talk about a large aperture (or f-stop) we’re actually referring to a small number. f2 is a large aperture. f22 is a small aperture. To make it even more confusing, f2 has a small depth of field (so the background is blurrier) and f22 has a huge depth of field (so you will end up with more in focus).

F-stops and aperture used to be pretty simple on an old-school camera. There were full stops. Every change in aperture was double or half the one before it. f8 lets in half as much light as f5.6 and twice as much light as f11. The advent of digital cameras though, has added a whole bunch of apertures/stops in-between. Some show 1/2 stop increments, and others (like my D90) show 1/3 stop increments. Oh dear! How confusing!

For the sake of learning though, the full f-stops are below. You can then use your mathematical skills or a case of trial and error to work out how this corresponds to your camera. For the record, there’s a really handy chart showing this on page 24 of Photography, Ninth Edition by London, Stone & Upton. It’s not a cheap book, but you might be able to pick it up on ebay from an ex student.

Full f-stops:

  • f1.4 (this is a big hole, a large aperture and a shallow DOF)
  • f2
  • f4
  • f5.6 (this is common for portraits and standard on a few fixed point & shoot film cameras)
  • f8 (a good starter setting as you’ll get a fair bit in focus)
  • f11
  • f16 (another handy tool is the “sunny 16” rule – look it up)
  • f22 (small hole, small aperture, huge DOF so more of the scene’s in focus)















Kell's aperture chart

Examples showing the different effects of changing aperture.



Depending on your camera lens, you might not be able to get a really large aperture. If you have a kit lens you might only be able to get down to f5.6 or f4. That’s not too bad, but you might not be able to get the effect you want, in which case you might just have to fake it using textures and layers in your post processing program.

These photos below were taken with the presets on my DSLR. These are the little picture icons on the dial. To be honest, I haven’t used these in years so it was an interesting lesson for me too.

Kell's d90 presets chart

Examples of the preset modes on D90 for this scene

But what about a point and shoot camera? Often they don’t have manual settings. Apparently mine does, but I don’t know how to change them. I have stated before that I’m pretty useless with my point and shoot camera…point and shoot is pretty much all I do use it for! Anyway, in the tests I did, my Sony Cybershot DSC-W300 chose the same aperture for all 4 pictures, but adjusted the shutter speed to compensate. We’ll go into that in another post, but the general gist is that a portrait setting or sports setting helps you get a blurrier background than auto does.

Once you learn about the shutter settings as well (which we’ll cover in another tutorial), you can play with the M (manual) setting and over-ride what the camera thinks is the best exposure in order to get the effects you desire.

I hope this information helped. I can’t give you tips specific to your camera but hopefully this information combined with your camera’s manual and a bit of research will help you on your way to creating some pretty bokeh and nice blurry backgrounds.


8 thoughts on “Aperture, DOF & those cool blurry backgrounds

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  4. Great write up. It is also worth mentioning that the closer to get to your subject, ie the closer your focus point, the more shallow your DOF will be and the more out of focus the background will be.

  5. Awesome tutorial! I took a photography class in late 2004 on how to use SLR cameras but I have forgotten a lot of it. Since I’m slowly getting back into my film cameras, I have been meaning to find an easy-to-follow tutorial on using the f-stops and shutter speeds to refresh my memory. Your post has helped me a lot and I am looking forward to your tutorial on shutter speeds now!

    • Oh I’m so glad to hear it was of use to you Jamie! Great stuff! =)
      Shutter speeds are very similar to apertures in how they work. Each full increment lets in half or twice as much light as the last. Same with iso. The key is putting all that information together.

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