I don’t know about you but I have to know how something “works”.
So for example when I start my car in the morning I have a general idea of what’s going on when I turn the ignition, when I start up my PC or Laptop I like to know whats happening with the loading of the operating system and the post startup tests, and so on!! I don’t always need to know down to the most technical of explanations but I like to have a general idea of what’s going on!!
Likewise with photography – before I press that shutter down to take a picture, I like / need to know how the scene I’m looking at will translate into a digital photograph on my camera or other optical device and to understand that you need to have grasp of the basics.
When you take a photograph – there are three things that always have to be set – either automatically – or manually by yourself – these are often refered too as the exposure triangle;
1. Shutter Speed
1. Shutter speed refers to the amount of time your camera allows light onto the digital sensor, for example on a sunny day your shutter speed will always generally be high as there is more light available and thus the shutter can open and then close very quickly as it captures that available that. On an overcast day or heading towards night when there is not so much light available, the shutter speed will slow down and the shutter will need to remain open for longer to let that light in.
A fast shutter speed allows you to “freeze” action and motion and in general hand hold a camera whilst achieving great results. As it gets darker or you are photographing perhaps indoors the shutter needs to stay open for a lot longer and sometimes too long for you to hand hold the camera and get a good result – this is just because a slow shutter speed starts to pick up any little movements you may make when taking the picture.
2. Aperture refers to the size of the opening in the lens that you are allowing light to travel through. You’ll see apertures refered too as F numbers and you’ll see these numbers like F2.8, F4, F5.6, F11, F16 appear on your camera when you are taking a photo. The primary function of an F number (or aperture) is to control the volume of the light that reaches the digital sensor. The confusing thing at first is the smaller ther F number, the larger the lens opening is – so for example an aperture of F2.8 lets in vastly more light than an aperture of F16 simply because the lens opening is very large at F2.8 The chart below will demonstrate this slightly better!
3. ISO. ISO refers to the sensitivity of your digital sensor to the light entering through the lens. Theres a great analogy from Bryan Peterson which I’ll use – think of the ISO as a worker Bee. We are about to take the same portrait picture of a friend in some shade and set our cameras up exactly the same apart from the ISO setting.
If my camera is set to ISO 100 that means I have 100 worker Bees who can fly out and gather any available light for me to make an image. If you set you camera to ISO 400 then you have 400 worker Bees who can fly out and gather that light for you. Who will record the photo faster? You will, as you will be able to gather the light 4 x quicker than I can as your camera is 4 x more sensitive to light due to changing the ISO setting. How does increasing the ISO help you take a picture? Well at a very basic level if we are hand-holding our cameras we need a “safe” shutter speed to shoot with to record the image correctly – if the shutter speed is too slow we may record natural movement in our hands and the picture then loses sharpness.
Taking a photo of our friend in the shade, my camera with ISO 100 shows a shutter speed required of 1/15th of a second to take the photo – this is generally too slow to record a good image, however your camera set to ISO 400 shows a shutter speed of 1/250th of a second – perfectly fine for taking a photo. Why is this? Your shutter speed is 4 x quicker than mine because you have set your ISO to be 4 x more sensitive – this means you can use a shutter speed 4 x greater than I can to record the same image.
Hopefully that makes some sense – there is a lot more variables to throw in but the exposure triangle always remains at the heart of any photo you take – a shutter speed is selected to open and let in light and then close in a set time period (set automatically or manually), an aperture is selected to allow a certain volume of light through into the camera (set automatically or manually) and your ISO is selected to set the sensitivity of your cameras sensor to the light that’s then gathered.
Next up I’ll go through some of the modes available on all digital cameras nowadays, what they mean and what’s best to use in certain situations.