When photographers talk about exposure, they’re usually talking about two things.
1) The brightness or darkness of a photo.
2) That arsehole of a client who used the phrase: “Can you do it for free? It’ll be good for your exposure.”
Bad jokes aside, a technical understanding of exposure (in the first case, of course) will help you to take better shots on your travels.
Nowadays, technology has advanced to a level where most casual camera users can take a semi-decent photo while relying solely on the automatic mode of their cameras and camera phones. But a proper technical understanding of exposure -and the tools that allow you to control it – will help you to explore more creative options, and hone your appreciation of the craft.
Many amateurs (myself included) tend to get intimidated by the jargon that comes with photography, but it’s really not that complicated to understand on a technical level. The hard part is applying these principles, and practicing on a regular basis.
Quite simply, how bright or dark a photo is. A photo that’s overly bright is overexposed, while a photo that’s too dark is underexposed. You can use any of the three following tools to control exposure: ISO, shutter speed and aperture. Each of these tools will also affect another element of the photo. More on that below.
Also affects: Noise
Have you ever taken a photo at night and noticed that it looks grainy or ‘fuzzy’, sorta like in one of those old movies you used to watch on VHS tapes?
This is referred to in photography as noise, and it’s directly affected by your ISO setting. A higher ISO setting such as ISO 2,000 will produce a brighter photo than one taken at ISO 100, but at the expense of making the photo noisier.
These days, most cameras (even on smartphones) are able to shoot at pretty darn high ISOs, so the best thing you can do is go out and take a couple of shots with your camera of choice, and take note of when the noise starts to become noticeable.
For beginners, this is probably the safest option to play around with, as long as you’re aware that higher ISOs will lead to noisier photos.
Also affects: Depth of Field
Without getting too technical about it, the aperture affects how much light will enter the camera. Aperture sizes are measured in f-stops, and denoted as (f/x number).
A high f-stop number (f-16, for example), means that only a small amount of light will enter the camera, while a low f-stop number (like f/3.5), means that significantly more light is allowed into the camera.
Aperture also affects a photo’s depth-of-field, which translates to how much of a photo is sharp, and how much is blurry. A low f-stop will give you a shallow depth of field (meaning that more of the background is blurry), while a high f-stop will have the entire background in sharp focus.
If you’re planning to take a portrait photo of a farmer, for example, and you don’t want people to take too much notice of the wheat field he’s working in, set it to a low f-stop. If you’re taking a shot of a scenic mountain range, a high f-stop would be more ideal.
Also affects: Motion Blur
The shutter speed basically affects how quickly the shutter opens and closes to allow light into the camera. It’s measured in fractions of a second, so a shutter speed of 1/2 would be slower than a shutter speed of 1/200. A low shutter speed allows more light into the camera, while a high shutter speed allows less light in.
You may have come across situations where you’re trying to capture something that’s moving quickly – like a car, or a grizzly bear running towards you – and found that the object you were trying to take is blurry. This is known as motion blur; the faster the object moves, the higher the shutter speed you’re going to need to capture it.
On a side note, be cautious about lowering your shutter speed too much, as it may cause your photos to turn out less sharp if your hands are unsteady. A good rule of thumb is to make sure that your shutter speed is 1/the focal length you’re shooting at.
So if you’re shooting with a 50mm lens, the slowest you should go in terms of shutter speed is 1/50.