(It’s all about the light!)
So, we’ve discussed cameras vs. phone cameras and some basic rules of composition. Ultimately, however, photography is all about light. The word Photo comes from the Greek for light and photography, as an art form, is about creating images from exposure to light. The camera is a tool that controls the amount of light that reaches your light sensitive substrate, whether that’s film, or a digital sensor. This article will just be an overview as there isn’t space for too much detail, but hopefully everyone can follow it.
There are three basic things that govern the amount of light required to make a correctly exposed image; The ISO setting of your film or sensor, (it doesn’t control exposure but it’s related to it), the shutter speed, i.e. how long the camera shutter is open for, and the aperture of the lens, basically, how big the hole is that the light comes through. I’ll cover each of these briefly, to give an idea of how they work and how to control them to create the image you want. Of course, you can also leave your camera/phone on Auto and it will sort all of these out for you but if you’re reading this, I’m guessing you’d like to know a bit more about what these settings mean and how to use them to get the best results for your image.
ISO actually comes from International Standardisation Organisation although camera ISO doesn’t directly relate to this organisation. In the days of film only, film sensitivity was referred to by an ASA or DIN number, typically between 50 and 3200, doubling each time (50, 100, 200, 400, 800, 1600, etc). In the 1970s these two (ASA & DIN), were combined into one, ISO. Digital photography has adapted the same references for digital sensors as are used for film to keep levels of brightness the same for digital and film. Adjusting this in your camera will alter the brightness of your image. The higher the number, the brighter your image will be. The setting you use, however, will also affect the grain or digital noise of your image. The higher the ISO setting, the more grainy or “noisy” it will be and vice versa, so you’ll need to balance what you want to achieve with the prevailing light conditions. As a guide, for bright, sunny conditions, set it to 50-100, for cloudy conditions, 400-800 and for night photography 1600 and upwards depending on the capabilities of your camera. Keep it as low as you can for the light conditions to avoid excessive grain. You can of course, also use a lower setting at night if you have a tripod to keep the camera steady and you want to minimise noise/grain. ISO setting should be balanced with the exposure settings that we will go through next.
Shutter speed (capturing movement)
The shutter speed, combined with the aperture, actually control your exposure, and these need to be balanced together to get the correct amount of light onto your film or sensor. The shutter speed is important and very dependent on what you are photographing. If you want to capture moving things, for example sports or wildlife, or moving water in waterfalls or rivers, even people walking, then the speed you select will give very different results. A slow shutter speed will result in blurring movement, and a fast shutter speed will freeze the action. The speed of movement will determine the most suitable shutter speed. Keep in mind too, that the slower the shutter speed, the more likely you are to get camera shake and you may need to use a tripod to keep things steady. Typical shutter speeds are in fractions of a second and anything longer than 1/60th second will be difficult to hand hold. Long exposure or slow shutter speed can be very effective in creating silky looking waterfalls in a landscape or blurring the motion of people or moving objects. The speed of the water or object will determine what shutter speed works best. A fast shutter speed, for example faster than 1/500th second is excellent for sports or wildlife photography to instantly freeze the motion. Experimentation is the key, as only you know what you want to achieve. The speed must also be balanced with the aperture you select so that you don’t over expose (too light) or under expose (too dark), your shot. If shutter speed is what you want to control, you can set your camera to shutter priority and it will automatically set the correct aperture within the limits of your equipment.
Aperture (depth of field)
The aperture is basically the size of the opening in your lens and is expressed as an ‘f’-number, e.g. f2.8, f8, f11 etc. The smaller this number is, the bigger the aperture (hole), and the bigger the number the smaller the aperture. So f2.8 will be a big opening whereas f22 would be small. The maximum/minimum will depend on your lens. The key benefit of adjusting aperture is depth of field control or how far into the distance things will remain in focus. The smaller the f-number, the less depth of field, and the bigger it is, the greater your depth of field. If, for example, you are taking a landscape where you want everything in focus, then select the smallest aperture (biggest f-number) you can for maximum depth of field, but if you are taking a portrait and you want to focus on the person’s face, then by selecting a shallow depth of field and low f-number, the background will become blurred and out of focus and the person’s face will remain sharp. Remember, aperture will need to be balanced with shutter speed, so If depth of field is most important to you, then you could select aperture priority on your camera and it will select the best shutter speed for your chosen aperture. Be careful though about lighting conditions, as it may be too dark or too bright for a suitable shutter speed to be chosen.
So here you have a brief overview and introduction to exposure. Experiment, and get to know your camera and what it can do vs. what you want. Ultimately, it’s about finding the right balance of shutter speed and aperture, and its all about the light!