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The exposure triangle for beginners, in plain Kiwi English

·5 mins
Help! I'm new

Every new camera owner hits the same wall. The photos look fine on auto, then you switch to manual and everything goes white, black or blurry. The fix is understanding three settings and how they trade off against each other. Photographers call it the exposure triangle. We think of it more like three taps filling the same bucket.

The bucket idea

Your sensor needs a certain amount of light to make a well-exposed picture. You control that amount with three things:

  • Aperture: how wide the hole in the lens is.
  • Shutter speed: how long the hole stays open.
  • ISO: how strongly the camera amplifies whatever light arrives.

Open one tap more and you can close another. The skill is choosing which tap to use, because each one also changes how the picture looks.

Stops: the only maths you need

A “stop” is a doubling or halving of light. That’s it. Go from 1/250 second to 1/125 and you’ve let in one stop more light, because the shutter is open twice as long. Go from ISO 200 to ISO 400 and the camera is one stop more sensitive.

Aperture uses f-numbers, which look odd until you learn the standard sequence: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22. Each step along that list lets in half as much light as the one before. Smaller number, bigger hole, more light.

Because all three settings speak in stops, you can swap them. One stop less shutter speed can be paid back with one stop wider aperture, and the brightness stays the same.

Aperture: how much is sharp

Aperture controls depth of field, the zone from front to back that looks sharp.

  • Wide (f/1.8 to f/4): soft, blurry backgrounds. Great for portraits, pets and picking one flower out of a garden bed.
  • Middle (f/5.6 to f/8): the sweet spot on most lenses, sharp and forgiving.
  • Narrow (f/11 to f/16): lots in focus, handy for landscapes where you want the rocks at your feet and the hills behind both crisp.

Don’t automatically wind it to f/22 for a landscape. At very small apertures diffraction starts to soften the whole image. On most cameras f/8 to f/11 gives plenty of depth with better detail.

Shutter speed: freezing or blurring

Shutter speed decides whether movement freezes or smears.

  • 1/1000 and faster: kids on a trampoline, surfers, birds in flight.
  • 1/125 to 1/250: people walking about, general handheld shooting.
  • 1/30 and slower: blur creeps in. Useful for silky waterfalls if the camera is on a tripod, a problem if it isn’t.

A common rule of thumb for handheld shots is to keep your shutter speed at least as fast as one over the focal length. So a 50mm lens wants about 1/50 or faster. On a crop-sensor camera, go a bit quicker again. Image stabilisation buys you some slack, but it only fixes your wobble, not a moving subject.

ISO: the volume knob

ISO brightens the image electronically. Low ISO (100 or 200) gives the cleanest files. Higher ISO lets you keep a usable shutter speed in dim light, at the cost of grain, which photographers call noise.

Modern cameras handle ISO 1600 or 3200 far better than older ones did, so don’t be scared of it. A slightly grainy sharp photo beats a clean blurry one every time.

New Zealand light makes this matter

Our light can be brutal. A clear summer day gives hard shadows and very bright highlights, and the gap between them can be wider than your sensor can hold. A few habits help:

  • Shoot early or late. The hour after sunrise and before sunset is softer and far easier to expose. We’ve rounded up some favourite spots in Auckland golden hour spots.
  • Watch the highlights. Turn on the blinking highlight warning in your camera’s playback menu. If the sky or a white shirt blinks, bring the exposure down.
  • Use the weather. A bright overcast day is a gift for portraits and bush walks. Check the MetService national forecast and plan around cloud, not just rain.

A handy starting point: Sunny 16

Before light meters were everywhere, film shooters used the Sunny 16 rule. In bright sun, set f/16 and a shutter speed close to one over your ISO. At ISO 100 that’s f/16 at about 1/100 (or 1/125 on most cameras).

From there, you can trade stops. f/8 at 1/500 lets in the same total light as f/16 at 1/125, because you’ve opened two stops and sped up two stops. It’s a neat way to practise thinking in stops, even if your camera’s meter does the work in real life.

Which mode should you use?

Full manual isn’t a badge of honour. Most working photographers live in a semi-automatic mode:

  • Aperture priority (A or Av): you pick the aperture, the camera picks the shutter. Best for portraits and landscapes.
  • Shutter priority (S or Tv): you pick the shutter, the camera picks the aperture. Good for sport and moving water.
  • Auto ISO with either: set a minimum shutter speed and let ISO float. Very practical for events and kids.

Use exposure compensation (the +/- button) when the camera gets it wrong, such as a bright beach or a dark bush track.

Practice that actually sticks

Pick one subject, such as a pot plant on the deck, and shoot it five times at five different apertures. Then do the same with a moving subject and five shutter speeds. Compare them on a big screen. Half an hour of this teaches more than a week of reading.

If you’d like feedback from real people, a local camera club is a great next step. The Photographic Society of New Zealand lists affiliated clubs, and most are friendly to complete beginners. You’ll find more starter posts under beginners.