Find out how angle of view relates to your lenses
Angle of view is a measure of how much of a scene or subject a lens can take in. Expressed in degrees, the angle of view can be measured horizontally, vertically or diagonally across an image.
It’s the focal length that’s key: lenses with shorter focal lengths are able to capture more of a scene in a single shot, while longer focal lengths offer a much narrower view. You can, of course, move your camera further away in order to bring more of a scene in to the picture or move closer to produce a tighter shot – or stay where you are and adjust the setting on a zoom lens – but the angle of view for the chosen focal length doesn’t change.
What does change is the relationship between the objects in the picture if you physically move closer or further away. Step forward with a wide lens and you’ll continue to capture more of the background relative to the subject of the photo. A long lens will continue to take in a much smaller portion of the background relative to the subject as you move away.
Focal length and angle of view
When photographers talk about a lens’ focal length, what they’re really concerned about is the angle of view. This is because the angle of view determines how a scene can be framed and composed. Long lenses with focal lengths of 200mm, 300mm or 400mm and beyond offer narrow angles of view that make it easier to isolate objects within a wider scene.
The drawback to having an angle of view of just a few degrees is that it’s equally easy to lose track of a subject, as a slight shift in the position of the camera can have a dramatic effect on which area is picked out by the lens. This problem is compounded if you’re following a moving subject, as anyone who’s tried photographing fast-flying birds up close through a 600mm lens will know!
Wide-angle lenses flip this problem on its head. Focal lengths in the region of 16-35mm are capable of sucking in a great deal of a scene in one photo, and consequently it’s easier to initially frame the shot and to recompose quickly.
The downside of taking in an angle of view of almost 100 degrees is that it’s easier for distractions to creep into the frame and it’s more challenging to make an object stand out from all the ‘noise’.
You can exploit the traits of different angles of view creatively. For instance, as well as being essential in confined spaces where you can’t physically move further from a subject, getting up close with a wide-angle lens means that you can capture both a subject and its surroundings in one picture. You can also play with scale, as objects closer to the camera will appear much larger in relation to those in the distance.
Longer focal lengths take in a much narrower section of the background. Not only does this make it easier to compose a ‘cleaner’ shot – a small movement of the lens is all it takes to find a more suitable section of the backdrop – but it magnifies that part of the background too.
You can use this aspect to make distant buildings, mountains or even the moon appear much larger in relation to the objects in the foreground. The trade-off here is that you’ll have to be shooting from a greater distance to squeeze them both into the shot.
As you’ll see below, sensor size makes a difference, with smaller sensors such as Nikon’s DX format requiring much shorter focal lengths to achieve a wide angle of view than their full-frame counterparts. But the way in which small sensors effectively increase the focal length of a lens can make them useful for long lens work.
How to select the right lens for the shot
The shorter the focal length is, the wider the angle of view. For instance, an 8mm fisheye lens may be able to take in a huge 180-degree view – and there’s a risk that your feet will inadvertently end up in the picture if you’re not careful. Super telephoto lenses, on the other hand, may offer an angle of view of just three or four degrees.
Below, you’ll find a list of common horizontal angles of view and the focal length required to achieve them with different sensor sizes.
Where you stand makes a big difference to how large or small distant objects appear.
Choosing the right focal length for a situation isn’t simply a matter of working out how large or how small you want the subject to appear in the picture: it’s also about the perspective and the overall look you want to achieve.
Here you can see the power that perspective can have. One photo has been shot from a distance with a 200mm telephoto lens; the other has been shot up close with a 20mm wide-angle.
The subject size might be consistent between the two images, but that’s about it. You can see how the wide-angle lens has captured much more of the environment, although having to shoot within such close proximity has resulted in some distortion on the features close to the camera. The telephoto lens doesn’t show the same distortion.