Taking control of your camera: Aperture and Shutter Speed

Notes for Shane

Here are a few quick things to remember from our course:

APERTURE (Av): Use this mode when you want to take a photo of flowers or a portrait.
  • A wide aperture (f4 to f5.6 will give you a shallow depth of field - blurry background. A narrow aperture f8 to f22 will bring more of your scene into focus - lots of detail).
  • If you are shooting in Aperture mode, make sure your camera's auto-focus is set to ONE SHOT with single frame shooting.
  • Remember to half press the button to focus (you'll hear a beep and your focus point will turn green) and then press the button the rest of the way down to take a photo.
SHUTTER SPEED (Tv): Use this mode when you want to freeze MOTION, such as when taking photos of a fast moving Archie or wildlife.
  • Make sure you set a fast shutter speed (1/400 and above) if you are taking a photo of Archie on the move.
  • For wildlife (like birds) you may need shutter speeds of up to 1/800 and above.
  • If you want to show motion blur you need slower shutter speeds (you may want to experiment with this) but if you are going to dial in a shutter speed of less than 1/50 you'll need a tripod or something to rest your camera on to reduce the effect of camera shake. 
  • If you are shooting in Shutter speed mode, make sure your camera's autofocus is set to AI SERVO and you are on continuous shooting.
  • Remember to half press the button to focus (you'll hear a beep and your focus point will turn green) and then press the button the rest of the way down to take a photo. If you hold the button down your camera will shoot multiple frames.

Remember in Aperture mode your camera will automatically set the shutter speed and ISO to achieve the aperture you want. In Shutter speed mode, your camera will automatically set the aperture and ISO to achieve the shutter speed you want. 

Hello and welcome to my camera course! If you are here you've probably been using your camera on Auto and are starting to get a bit frustrated with some of your photos. Are they sometimes blurred or out of focus? Perhaps the resulting photograph is not what you intended. Or perhaps you just really want to know what all those settings mean on your camera? You've come to the right place. We are going to talk about how taking control of Aperture and Shutter Speed can drastically change the way you take photographs. You'll be amazed at what you can achieve once you understand how to make these two settings work for you.

Lets begin by talking about light, because photography is all about light. A photograph is 'exposed' when you press the button on your camera the shutter opens and light hits your camera's sensor. The resulting photograph is determined by how much light you let into your camera (aperture) and how quickly you do it (shutter speed). It's that simple! We're going to talk through how to make these two settings work for you. Lets get started!

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The exposure triangle

The first thing we are going to discuss is how to get a well exposed photo.

A well exposed image is all dependent on how much light you let into your camera.

There are three factors contributing to a well exposed image, and these are often referred to as the exposure triangle.

  1. Aperture or f-stop (the size of the opening in your lens when you take a picture)
  2. Shutter speed (how long the shutter remains opens when you take a picture)
  3. ISO (the sensitivity of your camera’s sensor to light)

A helpful way to explain these elements is to imagine you are standing in a dark room with a window and curtains at one end. Aperture can be compared to the size of the window: A large window will let lots of light into the room. A small window will only let a little light into the room. 

Shutter speed is the amount of time the curtains stay open for. Curtains that are opened and closed quickly will only let a little light into the room. Curtains that stay open longer will let a lot of light into the room.

We can stretch the metaphor to imagine you are standing inside the room wearing sunglasses (ISO). Your eyes will be less sensitive to the light if you are wearing glasses and more sensitive to the light without them.

We’ll go through these elements one by one.

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  1. Aperture

This refers to how wide the opening in your lens is.The best way to understand aperture is to think of it as similar to the controls for the pupil of your eye: The wider your pupil opens, the more light is let in.

Aperture is measured in ‘f-stops’. 

A lens that is open to its widest aperture (for example f1.4, f2, f2.8, f4) will let a lot of light in. Its narrowest aperture (f16, f22) will only let a little light in.

Moving from one f-stop to the next doubles or halves the size of the opening in your lens (and the amount of light getting through).

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Aperture and Depth of Field

 

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When your camera lens is open to its widest aperture, it is letting in a lot of light, creating a shallow depth of field. 

This means that only a small part of your photograph will be in focus. 

This can be wonderful for creating photos with a blurry background such as in the photo of the bluebells above, this was shot at f2.8, only one of the bluebell plants is in focus. 

In the below example, the children are deliberately out of focus because I wanted to draw attention to the unexpected visitor in the background. The focus is on the fox with an aperture of f5.6. A wider aperture (of f2.8 for example) would have blurred the foreground too much and not told the story I wanted, that of my children playing, oblivious to the wild animal in the garden. A narrower aperture (of f16) would have put the children in focus and your eye would not have been drawn to the fox, the subject of this photo.

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As you ‘stop down’ and narrow your aperture, you’ll notice that more of your scene appears to be in focus. At f22, virtually your entire scene will be in focus. 

The next example was shot at f10, this is because I wanted to get the two adults and two children in focus. 

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HOT TIP: A shallow depth of field (small f-number = wide open aperture) is good for portrait photos or where you want to isolate your subject from the background. A large depth of field (high f-number = closed down/small aperture) is good for group shots or scenes where you want to include the detail in the background.

2. Shutter Speed

Shutter speed refers to the amount of time the shutter stays open allowing light in to hit your sensor. Your shutter speed determines the amount of motion you are including in your frame. Imagine you are photographing a cycle race. If your shutter speed is set to 1/20, the cyclist will simply be a blur across your frame (this can be a very pleasing effect). A high shutter speed of 1/1000 should freeze the motion allowing you to capture the cyclist in sharp focus. 

Have another look at the above photo, do you see each individual water droplet frozen in motion? The shutter speed used in this photo was 1/800, it was enough to capture the individual droplets of the fast moving water sprays.

The next photo shows another example of frozen motion. I managed to capture this Fish Eagle in flight using an very fast shutter speed of 1/1000.

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You may not always want to freeze motion in your photos, sometimes you want motion blur to show movement, to achieve this you’ll need to lower your shutter speed.

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HOT TIP: A fast shutter speed (1/500 and above) will freeze motion, a slow shutter speed (1/20) will allow you to introduce motion blur into your image

3. ISO

At the moment we are going to leave your camera's ISO setting to AUTO. But I have included the below information because it might help you understand why some of your photos appear grainy when you take pictures in low light.

ISO refers to the sensitivity of your camera’s sensor to light. A low ISO (of 100 - 250) will mean your camera is less sensitive to light, while a high ISO (1000+) will mean your sensor is very sensitive to light and so you will need less light hitting the sensor to properly expose your image. 

However there is a trade-off. As the ISO increases so does the digital noise (or film grain)  and the dynamic range (the camera’s ability to capture both lights and darks effectively) is negatively affected. Lets look at the two photos below. The one on the left of the couple was taken with an ISO of 250. This is a low ISO, I had lots of light streaming into my camera from the sun so I needed my camera's sensor to be less sensitive to light. I also didn't want a lot of grain on this romantic image. The photo on the right was taken indoors at a birthday party in a room with no windows, so no natural light. It was dark and in order to get a properly exposed photo I had to increase my camera's sensitivity to the light. In order to freeze the motion of the little guy coming down the slide, I needed a shutter speed of at least 1/400. At the widest aperture (f2.8) I needed to ramp my ISO up to 1250 to get a properly exposed photo. If you zoom in you can see how much grain there is in this photo.

ISO numbers start from 100-200 (Base ISO) and double in value. So, the ISO sequence is: 100, 200, 400, 800, 1600, 3200, 6400 and etc. The important thing to understand, is that each step between the numbers effectively doubles the sensitivity of the sensor. 

So, ISO 200 is twice more sensitive than ISO 100, while ISO 400 is twice more sensitive than ISO 200. This makes ISO 400 four times more sensitive to light than ISO 100, and ISO 1600 sixteen times more sensitive to light than ISO 100. 

What does it mean when a sensor is sixteen times more sensitive to light? It means that it needs sixteen times less time to capture an image!

Unless they are after a moody feel to their photographs, most photographers try to keep their ISO as low as possible to avoid noise. 

When there is plenty of light, you should use the lowest ISO to retain the most amount of detail and to have the highest image quality. 

As a general rule when you are outdoors on a bright sunny day you should be able to get a well exposed photo with a fast shutter speed using your camera’s base ISO (the lowest it will go - usually between 100 and 200). At an ISO of 100 there will be almost no grain or digital noise in your photograph.

If you are in shade you may find you need to increase your ISO if you want a fast shutter speed or a narrower aperture.

Likewise, when you are indoors, or taking photos at night when there is not a lot of light around, you will need to bump up your ISO to ensure you get a well exposed photograph.

 

Which setting should I change? Aperture or Shutter Speed? 

Think about what you are trying to achieve with your image. The easiest thing to do is to decide which of the following two factors are the most important for your image. 

SHUTTER SPEED

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* Is it important to freeze motion? (you’ll need a faster/higher shutter speed)
* Is it important to incorporate deliberate movement / motion blur? (slower shutter speed) 

APERTURE

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* Do you want a very blurry background, such as in a portrait in the example above? (wider aperture)
* Or is it important to have everything in focus from foreground to background, such as in a landscape in the photo below? (narrow aperture)

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Practice exercises

Of course the easiest way to really get to grips with all of this is to practise. So try and take your camera out a few times a week and take photos. You’ll soon be able to change your settings to achieve what you want without even thinking about it. 

APERTURE

Aperture challenge 1: Take a portrait photo of one person at your WIDEST aperture (f/4 if you can manage it) and see if you can get a blurred background with your subject in focus. You may need to get your subject to move closer to you and further away from the background to achieve this effect. I suggest a local park so you have lots of space to practice.

Aperture challenge 2: Take a family photo with everyone in focus, for this you may need a NARROWER aperture (f/8 or f/11). 

Aperture challenge 3: Find a flower bed with a variety of blooms in it (if at all possible at this time of year). Focus on one flower, try and take a photo with that flower isolated from all the rest (so it is in focus and the others are blurred). Think about what aperture you will need to achieve this? Focusing on the flower closest to you might make this exercise easier.

Aperture challenge 4: Take another photo of the same bed of flowers but this time you want them ALL in focus (no blurring). Think about what apertureyou will need to capture all those details?

SHUTTER SPEED

Shutter speed challenge 1: This is where Archie is going to come into his own! Again the local park is a good place to practice. Take an action shot where you will need to freeze motion. Archie on the slide, swing or roundabout will be good for this. Think about what shutter speed you will need to freeze him in motion (don't forget to set your auto focusing system to AI SERVO, continuous shooting)

Shutter speed challenge 2: Take an photo where you want to show motion blur (slide, swing or roundabout is good for this). You want a slow enough shutter speed to show the movement BUT also keep the stationary bits of the playground equipment in focus. A fast-spinning roundabout is probably the best equipment for this challenge or a fast-moving swing. A high slide, where Archie can pick up some speed might also work. For this exercise you will need a slow shutter speed. You might also want to rest your camera on something to help you focus and avoid camera shake.

I really hope you have found this course useful. I am here if you have any questions or problems. Please don't hesitate to call or email me and I will do the very best I can to help you! My contact details are at the foot of this page.