The Holy Trinity: Shutter Speed, Aperture & ISO

Digital photography technology is advancing so quickly that today’s DSLRs and increasingly even point and shoot compacts all have a dazzling array of features. If you’re thinking of buying your first big fancy camera it can be a hellishly confusing process. I am using a camera that is already 5 or 6 years old, a lifetime in digital technology and yet failing miserably to get my head around it’s capabilities. 

Before people come out on safari there’s often a question about what camera gear to get, and when out on safari I’ve often been asked what’s the secret to taking cracking photos every time. Firstly no one gets great photos every shot and furthermore I don’t think there is just one secret, it’s a whole combination of elements that go into each and every photograph. However looking back on the short time I’ve been taking photos, I would divide that time into before I understood the shutter speed, aperture and ISO nexus, and after. You can have the most expensive kit that money can buy but if you don’t know the basic concepts of how your camera works with light, then it’s all for nothing. For me it really was the great leap forward moment, not least because of the quality of your photos but also because you can start to have some influence over your results, rather than blind automatic mode luck. Never fear, it really is quite simple and if a Luddite like me can get it then so can you. I’ve seen the light go on over just a few short days on safari. Here’s a brief explanation to get you started.

What are shutter speed, aperture and ISO? 

Shutter speed

This is how much light is allowed to hit the camera sensor. It is measured in seconds (slow shutter speed) and fractions of a second (fast shutter speed); you’ll see 1/250 or 1/500 on your camera display for example. The way to think about it is that if the shutter speed is slow, you will be letting a lot of light into the camera. This is good if it’s dark, not so good if it’s bright. In wildlife photography terms we are often looking to freeze the action with a sharp photo, say a bird in flight or a lion running, to achieve this you will need a fast shutter speed. If you’ve got lots of natural light then this might not be a problem, otherwise, you might have to make up some light with the following features.


A small hole in your cameras lens that controls how much light can enter. You’ll see it right next to the shutter speed on the camera display with for example f5.6, f6.3 and so on. The way it’s referred to is confusing for stupid people like me, in the same way people talk about gears on a bike is back to front. So a small aperture, is a bigger number, say f20, not letting a lot of light into the camera and a darker picture. A big aperture would be a smaller number, say f5.6, letting a lot of light into the camera and brighter pictures. Technically this is because the number is an expression of the ratio between the aperture diameter and the length of the lens. 

What you also need to know is that aperture controls depth of field. By depth of field we are referring to how much of the image is in focus. The fashion at the moment in wildlife photography is to blur the background in order to make the subject stand out, you see this a lot with pictures of birds or charismatic animals like lions or chimpanzees. This is done using a large aperture, the lowest you can go. Conversely if you were taking a landscape shot, or a wider angle shot of an animal in its habitat, you might want more of the background to be in focus. This time you’ll need a smaller aperture, f10, f11 and up for example. Remember that means you’re going to need more light.


This is how sensitive your camera is to light. It stands for International Standard for Organization, don’t ask me why. Generally you want to keep this as low as you can, the reason being that a higher ISO produces more noise and grainy images. On safari for example you’re often faced with too much light if anything, so keep your ISO down at 2, 3, or 400. Increasingly the higher end cameras are capable or operating at very high ISOs without any discernable effect on the image, you can see this on photos where the photographer has listed the capture specifications, ISO 12000 or something crazy like that. That is certainly one way in which money can buy you a better photograph. But the point is there are some situations in poor light, a pesky leopard pops out on your way back to camp after sunset, when turning up the ISO might just be the only way to nail the shot.

So how do they all fit together?

Now that you’re grasping each of these factors individually, you can start to understand how they influence each other. You will need to spin that scary wheel thing around to M for manual mode and work out how to change each setting, you’ll need the manual for that. With a good bit of experimentation, once you go to manual, you’ll never look back. To see how the different dynamics can play out, here are a few examples with the settings underneath.

Firstly the clean background sharp subject shot. This is standard fare for wildlife photography. I tend to keep my cameras settings set up for this shot when starting out in the morning. The largest aperture you’ve got, a high ish shutter speed and a low ISO. It works great for these portrait type images when you’re really trying to bring out the colors and textures of the subject itself.

Secondly a landscape shot. The first one when the sunset light wasn’t great, another with a lot better light and one before the sun had come up. In both cases the aperture is small, so you’ll notice I had to make up for the lack of light in the first image with a very slow shutter speed. Just about doable as I had a monopod to keep the camera still. That’s why you see landscape chaps using great big tripods, as they are operating in very low light, when even the slightest movement will throw the shot out of focus. Often it’s better for the image to be somewhat underexposed rather than blowing the sky out, you can always recover lost light and colour editing your image later. There are infinite interplays here. Of course as is the beauty of photography, you don’t have to take what is written here as gospel, challenge yourself in different situations and see what works for you.

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