A Very Detailed Guide to the Exposure Triangle | Shutter Speed
Tuesday 19th February 2019
In my first post in this series of photography tutorials for beginners I offered some practical tips to help you get started. Today I’m going to assume that you have been taking photos on full automatic mode for some time, and that you are interested in taking more control of your camera settings and exploring the semi-automatic and manual modes that your camera offers.
A detailed Guide to the Exposure Triangle
Let me preface this tutorial by busting a myth. That myth is that in order to be a ‘proper’ photographer, you need to shoot in full manual mode. I am a professional photographer, and when I am working I mostly shoot in aperture priority mode. The reason I do this is because it is fast, it is efficient, and it allows me to capture the images I need to capture as quickly and effortlessly as possible. However, that’s not to say that learning to set your expore manually is pointless! It’s essential to know what each of the three components of exposure do and how changing them effects your final image.
Although I shoot 90% of a wedding in aperture priority, there are always moments where I choose to switch to manual exposure to be in full control, for example when I’m capturing the confetti throw and am walking backwards as the couple walk towards me through a tunnel of hands, or during the evening dancing when the light is continuous and low, and I am using my flash. By learning the exposure triangle and being comfortable with shooting in full manual mode, you give yourself options, both technical and creative.
In this three part exposure triangle guide I will talk you through the exposure triangle so that you understand how shutter speed, aperture and ISO shape your image, as well as how you can use each of them to tell stories, capture the moment and make photos that you are proud of.
The Three Components of the Exposure Triangle
Your camera controls how much light enters through the lens and hits the digital sensor or film strip in three ways, through your shutter speed, aperture size and the sensitivity of your sensor or film (ISO/ASA). Combined, these settings refer to your ‘exposure’ which can be balanced, too bright (over-exposed) or too dark (under-exposed).
While you may aim for a balanced exposure in 90% of your photos, sometimes it is ‘correct’ to have an under or overexposed image. For example when you want to create a silhouette, it is necessary to underexpose your image. At the other end of the spectrum, if you want to shoot into the sun (for example at sunset) and still keep the detail in your subject’s face, then it is necessary to overexpose your image.
This tutorial on the exposure triangle will be a long one, as I don’t believe in skimping on detail! There are plenty of surface level listicles out there for you to peruse if that’s what you’re after, but this tutorial will be very detailed and offer you lots of tips and advice for really getting to grips with your camera settings. As such, I’ve split the tutorial into three separate posts. In this first part I will explain what shutter speed is, how it shapes your images, and help you understand how to choose the correct settings for your photography.
What is Shutter Speed?
Shutter speed is simply the amount of time your digital sensor or film is exposed to light for, beginning from the moment you press your shutter release. Another way of describing shutter speed is the length of your exposure.
Creatively a very fast shutter will allow you to freeze action, for example someone running, jumping, or moving very quickly. It’s essential for sports photography, and for capturing children at play. A very fast shutter speed will also allow you to capture individual raindrops falling, blossom petals falling from trees in the spring, the moment lightning or fireworks light up the sky, or the arc of liquid rising from a teacup that has just been knocked over.
At the other end of the spectrum, a slower shutter will help you to capture motion in a different way; through blur! I’m sure you’ve seen photos of waterfalls looking like a sheet of silk, or car headlights painting trails along a highway. Both are examples of a slow shutter.
How to get started with manual shutter speed
If you’re coming from full automatic mode, then I encourage you to find the ‘shutter priority’ mode on your DSLR or mirrorless camera. This is a semi-automatic mode that allows you to set the shutter speed. Once you have made your selection for shutter speed, the camera will then choose an aperture setting to match. Think of it like learning a new swimming stroke; you need to work on the arm movement, leg movement and breathing separately in order to master the stroke and put it all together.
Shutter priority allows you to focus on your shutter speed settings without worrying about aperture selection and ISO at the same time.
Shutter priority mode is usually marked on the camera dial as Tv or S. When you use shutter priority or aperture priority mode, you also have the option of setting your ISO. I recommend you set ISO to ‘auto’ to begin with just to get it out of the way.
Now that you have isolated the shutter speed setting, have some fun! Why don’t you try photographing some sport – a child’s football game, or a friend running, or a toddler at play. Set your shutter speed to 1/100 then 1/1000 then 1/4000 and take the same photo to see how the difference between settings. You’ll soon get a feel for it. I suggest playing with a fast shutter to begin with, as it doesn’t require any additional equipment. Long exposure photography requires a tripod, which you may or may not have if you’re a beginner. If you do have one to hand or can make do with a chair or wall for your camera, by all means experiment with a longer shutter speed setting too!
A quick rule of thumb to avoid handheld photo blur
Finding your ‘slowest viable shutter speed’. When you are shooting handheld, you will find that there is a shutter speed setting below which your photos come out blurry, no matter how still your subject is. This is because your hands shake! Thankfully shaking hands are quite simple to compensate for, and there’s a rule of thumb for you to learn to make life nice and easy.
The slowest viable shutter speed is the reciprocal of your focal length, or your equivalent focal length if you are using a crop camera. For full frame cameras this is easy and doesn’t require any maths. A 50mm lens requires a shutter speed of at least 1/50; a 135mm lens requires a shutter speed of at least 1/135 (or the nearest setting e.g. 1/125 or 1/160) and so on and so forth. The longer your lens, the faster your shutter needs to be in order to avoid motion blur from your shaky hands.
What is ‘equivalent focal length’, you ask?
If you put a 50mm lens on a MFT camera (e.g. a camera made by Olympus or Panasonic) then you are dealing with a 2x crop factor (compared to full frame). Your 50mm lens now requires a 1/100 shutter in order for you to avoid handheld blur. If your camera is an APSC camera, then your crop factor is 1.5x (Fuji or Nikon) or 1.6x (for Canon).
Blurry photos resulting from an incorrect shutter speed setting is something that beginners often struggle with, but it’s so easy to avoid once you know what’s going on! Sometimes even the full automatic mode on a camera can get this wrong, choosing a shutter speed that while ‘correct’ will never allow you to capture a blur free image handheld.
I hope you have found this tutorial helpful and that it has encouraged you to dip into your settings and get to know your camera a bit better. In the next part of this three part tutorial I will discuss aperture, what it is and how you can use it as a creative tool in your photography.