Tutorials

Explaining apertures with puppies

Despite photographing lots of dogs prior to this I naively thought that I’d be able to line up eleven calm and collected Labrador puppies to demonstrate the effect of different apertures on a photograph.

Do these look calm and collected to you?

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Despite the challenging subjects I hope that I can help you understand the fundamentals of using different apertures and how this affects a photograph.

To start off there are three things that are all intertwined in a photograph, these are your shutter speed, ISO/ASA and aperture. Shutter speed is the length of time your camera shutter is open for. This is important depending on what you are trying to photograph, if you are wanting to freeze action then you are going to want a fast shutter speed such as 1/1000 of a second. While if you wanted to create motion blur then you would want a slower shutter speed, for example, 1/60th of a second.

A shutter speed of 1/1900 of a second helped to freeze this leaping puppy

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ISO is a way of setting the sensitivity of the camera sensor. The lower the ISO number (e.g. ISO 100), generally the better the overall quality of the image. However, the lower the number the more light required for an exposure. A sensor set up at ISO 100 requires a shutter speed four times longer than a sensor set up with ISO 400. With ISOs you have to decide what you want to prioritise, faster shutter speed or better quality, you have to find the compromise you are happy with for the situation at hand.

Tired puppy at ISO 200

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Crop of puppy showing high levels of detail at low ISO

ISO 200 crop

Then there are apertures… This dictates how deep the depth of field will be in the photograph. For example f1.4 has a very shallow depth of field that is helpful for isolating a subject, while f11 has a large depth of field that means everything in a composition can be sharp. Again though there is a twist as the smaller the f number the larger the amount of light let into the lens, meaning faster shutter speeds.

At f1.4 the depth of field is so shallow that only the eyes are in focus

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If one of the three factors change, then it affects at least one of the two other factors. For example if your camera is set up with ISO 400 and aperture f5.6, showing a shutter speed of 1/250 of a second and you want to increase your shutter speed then you can lower your aperture a stop to f4 (which will double your shutter speed) or another stop to f2.8 (quadruple your shutter speed). Alternatively if you don’t want to change your aperture then you can increase your ISO to 800 which would also double your shutter speed.

Using puppies was a difficult choice…

My intention for this blog was to have a wonderful selection of shots showing eleven puppies sat in a line using a variety of different apertures to show how this affects depth of field. The owner Ruth Mercer, who very kindly let me photograph the puppies, said the best time to do this would be when they’re being fed. As the birds eye view picture clearly shows, my dream of a nice orderly line was never going to happen! Why I thought this was possible with these little bundles of energy was beyond me. No matter though, the whole experience was utterly heart warming. And all is not lost as I did obtain some shots that highlight the difference in depth of field caused by different apertures.

Puppy at f1.4

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Puppy at f10

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You can see that with the second photo the depth of field is much greater than the first. This in turn shifts the focus away from the isolated, in-focus puppy in the first image to the whole scene of the second image. Note how your eye should be drawn a lot more to the bottom of the black puppy a lot more in the second image because it is in focus.

Despite being a rather unusual way to highlight how different apertures can affect the image produced, I hope this puppy inspired explanation has helped further your understanding. The lens used for the majority of these shots was the XF23mm f1.4 r which offers very fast autofocus and a very shallow depth of field, using f1.4, to give the photographer the greatest amount of control through a wide aperture range (f1.4-f16).

The take home message is that a small f-stop number allows you to create a very shallow depth of field to help isolate a subject. While a large f-stop number will mean that a larger proportion of the content in the picture will be in focus. To finish with here are a few more shots of the puppies, generally using a shallow depth of field to keep the focus on these adorable little characters. You can also check out a video of this adorable experience here by Ellice Dart.

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