Focal Lengths and The Difference Between Wide and Long Angle Lenses

Focal Length- (noun)

-the distance between the centre of a lens or curved mirror and its focus.

-the equivalent distance in a compound lens or telescope.

Lenses, in photography fall between a vast range of different focal lengths. With the widest commercial lens in production coming in at 6mm produced by Nikon and the longest commercial focal length coming in at 1200mm produced by Canon. 

The key thing to understand about focal lengths is that the wider the lens, the more of a scene you will capture and the longer the lens, the more zoomed in the image will be. I’ve included below a visual guide to help you understand:

For all of these images, the photographer would have been stood in exactly the same place. So, as you can see, the photograph taken with the 18mm lens covers a vastly more of the scene in front of the photographer than the photograph taken with the 300mm lens.

However, the focal length of a lens doesn't only determine how much of a scene is captured, it also has an influence on the way it is captured. Wider angle lenses tend to distort the perspective of space by exaggerating the size of anything in the foreground and compressing the size of anything in the background. 

Below are two images taken of the same corridor in roughly the same position. 

It is clear to see that the top image seems to have a much healthier and normal perspective on space with both the foreground and background being in good proportion. This is because the focused “focal length” of the human eye is around 50mm, and so the relationships of space produced by 50mm lenses are much more familiar to us. However, only when you look at the lower image, seen in relation to the top image can you see that the foreground looks much more spacious and the background looks a little compressed. The top image was taken with a 50mm lens and the bottom with an 18mm lens. 

Wide angle lenses are often used when photographing houses for estate agents or for any other form architecture. This is because, firstly, it isn't always possible to photograph inside of a building with a longer focal length because rooms are often too small. Secondly, they generously exaggerate the sense of space and perhaps grandeur within a building. 

Longer focal lengths  (longer than 50mm) however, compress space and are often used in portraiture. This is because when using a wide angle lens to photograph someones face it will distort their features, can make their head seem more oval and also exaggerate the size of their nose etc. Where as longer focal lengths, although they do still distort the perception of space, it is generally to a lesser extent and more often than not it will be “flattening” to the subjects features. I.e. if a subject has a big nose it will cause their nose to appear shorter. 

Below I have included two photographs, the first taken at 24mm and the second taken at 100mm. 

For both of these photographs, the model (my friend) had been standing in exactly the same position, and were taken seconds apart from each other. It is clear to see from this pair of photographs and the pair above, how drastically your choice of lens can affect the results of the captured image.

Thanks for reading !

Please feel free to check out my website at www.josephrigbyphotography.co.uk