● Welcome to the “Always use auto” article, this article covers the three fundamentals of photography (ISO, shutter speed and aperture) if your preferred learning style is through reading please continue, if you are more of a visual learner please see my website for the five videos I created illustrating the content of this article:
● This information is aimed at novices who own or have access to a Digital SLR, who currently use it on automatic and would like to make the most of its’ features. This article will cover the three fundamental principles that will enable you to operate your digital SLR, these are ISO, Shutter Speed & Aperture. The first section covers ISO, the second shutter speed & how to freeze or blur movement, the third on shutter speed & exposure, the fourth aperture & exposure and fifth on aperture & depth of field.
● What is ISO? The ISO controls how sensitive to light the cameras sensor is? What is a sensor I hear you ask? An image sensor is a solid-state device, the part of the camera’s hardware that captures light and converts what you see through a viewfinder or LCD monitor into an image. Think of the sensor as the electronic equivalent of film. An image sensor detects and conveys information used to make an image.
● In the days of 35mm cameras you would buy different speeds of film, the options of sensitivity of the film were ISO 100, 200, 400, 800 and so on, in those days you picked one type of film and stuck with it for the 24 or 36 shots, nowadays we have the leisure of being able to change the sensitivity of our sensor using the ISO controls for every shot we take. Your digital SLR will have an ISO range starting at around 100 ISO going up to 6400 or even more!
● At ISO 100 you will have the best quality image, at ISO 6400 you will have the worst quality image. The faster the ISO the grainer the image. So why use fast ISOs? The reason being if you don’t have enough light available to take a successful exposure a compromise needs to be made, so you sacrifice some of the image quality to make the cameras sensor extra sensitive to help ensure a correct exposure. So is anyone feeling confused, if so no problem let’s go through ISO step by step on your camera.
● Note I use a Canon 5dmkiii or mkii you don’t have to use a Canon to do the practical element of this course, the settings will be similar across all digital SLRs, the buttons and menus will have a slightly layout.
● If you would like to go through this practical demonstration of ISO find a relatively dark area, pop the camera on a tripod and set the camera mode to M for manual. Select these approximate settings: put your ISO on 100, put your shutter speed on 1/60 and put your aperture on f/8, at this stage don’t worry if you don’t understand what these stand for we’ll be covering all the settings as the article goes on. Run a test shot and hopefully you’d expect to see a relatively dark image (this may vary per camera set up).
● Now don’t touch the shutter speed or aperture for now, we will come to these functions at later stages in the course. Press the shutter release to take a photo you will see a dark not very interesting image, now change the ISO to 200 you see the image is slightly brighter, now 400, then 800, 1600, 3200, and finally 6400. With each increment you’ll have noticed each photo is a lot brighter this is because the sensor has become more sensitive, if you zoom into the images you’ll notice the quality slowly decrease, there will be increasing levels of noise (messy coloured dots of the image).
● The key thing we have learnt here is changing the ISO does two things it increases the sensitivity to the sensor and it affects the final quality of the image. I suggest you practice using this feature a couple of times, so you get used to finding the buttons on your camera and fundamentally understand why you chose these settings
● In our next lesson we take a look at shutter speed. We will learn how to freeze action like a fast motor car or blur action like a waterfall.
2) Shutter speed & freezing/blurring action
In this section we’re going to look at shutter speed and how it can freeze action or blur movement. What is shutter speed I hear you ask? After the light passes through the lens it travels to the little doors that cover the sensor (where our image is recorded) you choose how long these little doors are open for, this put very simple is shutter speed.
The shutter speed can range greatly, you could have a long exposure of 30 seconds or very short exposure 1/4000 of a second, the range you have will vary per camera.
As a quick guide you can handhold a camera from about at a shutter speed of 1/60 of a second onwards, lower than that and you’ll need to use a tripod. For the purposes of teaching I use tripod to take away the variable of handshake, when I’m at work as an event photographer I rarely use a tripod, whereas a landscape photographer would probably use one every time.
Let’s try a practical demonstration. Find a friend and ask them to stand in front of the camera and get them to wave at you. Set the camera to an ISO of approx. 400 and set the mode to dial to TV (shutter speed priority). Take your first photo with a shutter speed of 2 whole seconds, then 1 sec, ½ sec, ¼ sec, 1/8, 1/15, 1/30, 1/60. 1/125, 1/250, 1/500 and finally 1/1000.
As you can see the shutter needs to be reasonably fast to be able to freeze action. If you want to blur action like a waterfall you’d start at around 1-3 seconds and see how you go from there.
Our next section will cover shutter speed again but this time its effect on exposure.
3) Shutter speed & exposure
Please note once again we will be using a tripod for this section. I would like you to set your camera mode to Manual (look for the M). I would then like to set your ISO to 100 and your aperture to f/8.
Find a scene it can be anything, I’ve chosen a nice garden view. We are going to be changing the shutter speed across several increments to look at how it effects our exposure. Remember the term shutter speed just means how long the little doors in front of the sensor are open for.
I would like you to take several photographs each time changing your shutter speed to the listed setting. Firstly take your first photo with a shutter speed of 2 whole seconds, then 1 sec, 1/8, 1/15, 1/30, 1/60. 1/125, 1/250, 1/800 and finally 1/2000.
As you can see you the faster the shutter speed the less light hits the sensor and the darker the final image is.
You will be starting to gather photography is all about trade-offs, what is your priority? Is your priority the final quality of the image, is your priority to capture a moment of fast action or is it to get the correct exposure taking a shot at night time? Each time you take a photo a compromise will often need to be made. I hope you are starting to understand how shutter speed has two distinct effects on your final photo: the exposure and how it captures action. Please do keep practising shutter speed so really gets into your head how it functions with repeated use.
In the next section we are going to look at aperture and its effect on exposure.
4) Aperture & exposure
Please note we will be continuing to use a tripod for this section. I want you to set your camera mode to Manual (look for the M). I would then like to set your ISO to 100 and set your shutter speed to around f/1/60 of a second, by now you should hopefully be familiar with the dials on your camera to find these functions.
Find a scene outdoors it can be anything, I’ve chosen a nice garden view. We’re going to be changing the aperture across several increments to look at how it effects our exposure.
So what is aperture? Aperture means how much we open up the lens to let in light. Within any lens there are blades that open to differing sizes allowing different amounts of light to pass through the lens and hit the camera’s sensor. These different sizes are referred to as “f stops”. Each lens has varying f stop range, the lens I will be using today has an f stop range f/2.8 to f/22. f/2.8 is the widest aperture and f/22 is the smallest aperture.
Now don’t worry if this is starting to sound too technical for you, once we’ve been through this practical section the concept will start to twig and it becomes clearer the more you familiarise yourself with it.
So let’s go through the different settings to find out how aperture affects the exposure of your photograph. To start please select an aperture of f/2.8 take a photo, then f/4.0, f/5.6, f/6.3, f/ 8, f/11, f/13, f/16, f/18 and finally f/22.
So as you can see the more we open up our aperture the more light enters the camera and the brighter the exposure. I suggest you practice this a few times to make sure it is clear in your head.
In the fifth and final section we will be looking at aperture again but this time how it affects depth of field.
5) Aperture & depth of field
In this section we will be looking at aperture again, but this time in terms of how is affects depth of field. What’s depth of field I hear you ask? A basic definition of depth of field is: the zone of acceptable sharpness within a photo that will appear in focus. In every picture there is a certain area of your image in front of and behind the subject that will appear in focus (also known as blurred backgrounds). You will start to see phones now have a filter that achieves a similar but it’s not as pretty as the depth of field created by a digital SLR.
In this section I will be using the camera on the tripod again and I will be using a longer zoom lens, the reason for this is a accentuates depth of field more, so I can more easily illustrate to you how changing the aperture value changes our depth of field, (you don’t have to use a lens like this note).
I would like you to set your ISO to A for auto, I wouldn’t normally use auto but for the demonstration it’s handy. If you would like to manually set it, choose 100 if it’s a sunny setting and 400 if you are in the shade.
I would also like you to select AV mode, this means “aperture priority” (or aperture value), the shutter speed will automatically chose the appropriate setting to obtain the correct exposure.
I would like to you choose scene where you have lots of space between the subject and the background, for today’s example I have chosen a close by flower with lots of garden distant away in the background. You don’t have to choose a flower it could be for example a person up close and a beach view far away.
Each lens will have a slightly different aperture range, the lens I am using today has a large aperture of f/2.8 through to small aperture of f/22. When I set my aperture to for example f2.8 and then i zoom the lens in, the aperture stays at f2.8, you may find when you zoom your lens in the aperture may get smaller. For example if you have selected an aperture of f/4 it might well change to f/5.6 as you zoom in, don’t worry this is normal for many consumer level lenses.
So let’s work our way through the various apertures to see how effects the depth of field (aka background blur. I would like to select the largest aperture on your lens, on my lens this is f/2.8 take a photo, then
f/4, f/5.6, f/6.3 f/8, f/10, f/13, f/16 and finally f/22.
So as you can see changing your aperture really effects the depth of field and now you understand it more it should help you to get much more creative with your photography. I suggest you practise this a few times over so you learn the principal and before you know it it’ll be second nature.
An extra challenge if you fancy it?
So that bring us to the end of the Kay Ransom Photography “Always use auto” article and practical course notes. I hope you’ve enjoyed the information and have gained a much better understanding of your camera. I look forward to seeing your photos using the hashtag on Instagram and twitter. #RansomPhotoLessons
If you’d like to take a look at the videos that support these course notes, feel free to take a look here:
These photographs were taken at the wonderful Cerney House Gardens in Gloucestershire https://www.cerneygardens.com/