Don’t forget that every aperture has a purpose and reason you should use it.

The first arrow ever fired from inside to outside was probably shot through a doorway. I’m guessing, as I wasn’t there, but I think there is a good chance that is true. Whoever fired it may have realised quite quickly that firing from an open doorway didn’t provide much protection from the guys firing arrows back – if he got to think that long. We didn’t do away with doorways but in preparing ourselves for future attacks we may have decided that shooting from a window was a better idea as it a bit safer. Once we realised that small windows were better than big ones we may have slowly progressed to the understanding that the optimum aperture for shooting arrows at attackers was a slit in a thick wall with a wide interior so we could angle ourselves to fire in a wide arc while remaining well concealed. When the arrow slit was invented it didn’t kill off the small window, the large window or the door way, as those various sized openings in walls still had a reason to exist as they each suited particular occasions. A castle might have doorways for walking in and out of, big windows for letting in the light, small windows for ventilation and arrow slits for killing people from.

You may have already guessed where I’m going with this, but if you haven’t we’re going to take a look at the apertures we have on offer to us as photographers and the situations in which we might make use of them.

The apertures that photographers use are also designed to suit specific purposes and most lenses supply us with at least eight different full-stop aperture settings so that we can achieve at least eight different effects. However, a survey I did a while ago demonstrated that most photographers use only a few of those aperture settings and fail to make the most of what their lenses offer. We have a range of apertures for a reason, but most of us use the same few settings all the time. Search your archive by f/number to find out what you aren’t using and how your choices restrict the images you make.

Why we need eight apertures

I guess we all know that the main function of an aperture is to control the flow of light entering the camera – wide aperture for more light; small aperture for less. That’s just the basics though, as careful photographers consider also the quality produced when certain apertures are used. Physics dictates that the widest and smallest apertures are not those at which best image quality is produced. The optimal settings for sharpness and resolution tend to be in the central area of the range – usually between f/4 and f/8. At these settings we generally achieve best overall sharpness, the most consistent resolution from the corners to the centre of the frame, and the least vignetting.

While those central apertures are indeed the best when it comes to reliable quality they aren’t very exciting. They are safe and sensible, but if you stick to them the whole time to ensure you are producing the best technical results you risk missing out on what most other people judge pictures on – creativity, drama and atmosphere.

We have eight apertures because each produces a different look. Depth-of-field control makes up a significant part of that difference and the ability of a wide aperture to force the viewer to look where you want them to look. We think of depth of field as ensuring everything from the foreground to the distance is sharp, but selective focusing with a wide aperture can ensure that only what you want people to see first is sharp. Selective focusing with a wide aperture gives you control of the viewer’s eyes and attention. A wide aperture might create soft edges and a bit of corner shading, but what it loses in quality it makes up for in the excitement of a focused subject against a dramatically blurred background.

Modern lenses are moving towards much better performance at the widest apertures and, while f/1.8 will never be as efficient as those safe middle settings, in some lenses and for some purposes it is often already good enough. Wide settings on a fixed focal length lens will produce much better quality then the same aperture on a zoom lens (with all other things being equal) so there is much less reason to avoid them.

Bring some sparkle, excitement and dynamism to your creative work by using a more daring aperture – not every time, but far more often than you might be doing at the moment.

Captions

  1. Sometimes we need front to back sharpness, such as here where we want to see the man and the view. f/8

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  1. Sometimes though we want to make the people stand out from the background, but while still what’s behind them clearly. f/2.5

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  1. Here the subject is the iPad mini, so I wanted that sharp and the rest of scene soft so you would know where to look first. f/1.2

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4. Really wide apertures are brilliant for lifting a head-and-shoulders framed portrait out of a scene while creating a beautifully blurred background. Most of the time no one will care that f/1.2 isn’t the most technically perfect aperture.

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  1. Some people consider f/4 to be wide and risky, but it creates a much less exciting effect than the dynamic f/1.2

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Damien lives and breathes photography, and is a former editor of Amateur Photographer magazine. When he isn’t shooting he’s writing news or testing the latest cameras and lenses for websites, such as www.dpreview.com, and magazines such as AP and British Journal of Photography. He also teaches, showing photographers how to get the best from new or existing equipment and how to shift their photography to the next level. His passion is street photography, but he really loves all areas of photography. Based in the UK he holds regular workshops in London and around the country.