There’s an old photographers joke that all cameras come with zoom lenses; they’re just known as legs.
Bad jokes aside, we thought with all the focus on Nokia’s excellent zoom lens in the 1020, it was time to have a look at a few of the basics about zooming in and out: What is a zoom lens? How long has it been around? Why do we need it? And how should we best use it?
What’s the difference between prime and zoom lenses?
A lenses which does not have a zoom function is known as a ‘Prime lens’ or a ‘Fixed Focal Length’ lens (FFL). These often come in ‘classic’ sizes, such as the widely used 35mm lens. (The reason it is 35mm is that this is the perspective that most closely echoes our own field of vision). These lenses also have limited distortion and typically very large aperture capabilities.
A zoom lens by contrast offers a pre-defined range of focal lengths, (for example 17mm – 40mm or 70mm – 200mm). This enables the photographer to a wider variety of shots without having to dramatically alter their own position. Such lenses are often therefore regarded as being more versatile and are useful for subjects with a changing dynamic, (such as photojournalism or sports photography – or trying to get a picture of your kids!)
Ultimately, any lens is a compromise of factors. This is usually a balance between image quality, weight, size, cost, aperture, focal length range, noise and performance.
First people to zooooom
The earliest zoom lenses were used in optical telescopes as far back as 1834. These telephoto lenses had moveable elements which adjusted the focal length. However, they required refocusing the image after each change in focal length. (This type of lens is now known as a varifocal lens).
It wasn’t until the early 1900s that we got nearer to a recognisable zoom lens which retained focus even as the focal length changed (known as a parfocal lens). These early lenses, however, were mostly used in cinema cameras. Then, in the mid 1950s, the first zoom lenses were manufactured for a stills camera by Heinz Kilfitt in Munich. (The same firm were also responsible for the first ever macro lens).
This is one of the reasons why, on all the classic shots of photojournalists throughout the twentieth century, they have two, three or even four cameras hanging around their necks; each one would have had a different focal length lens. (And maybe a different speed film too). It wasn’t until relatively recently that zoom lenses had the same quality as a prime lens.
Compression of space?
It is immediately obvious that a wide angle shot and a zoomed in shot have very different visual properties. This is often known as ‘lens compression’ and there are a lot of myths about how this effect occurs. A wide angle lens will make the distance between your subject and the background appear greater, whereas a telephoto lens will ‘flatten’ the image and make them appear closer together. But the lens is only a part of this situation; the rest is about the angle of view and your distance from the subject. So the telephoto lens itself doesn’t affect perspective, but the fact that you are using it means you are further away from the subject and that does change the perspective.
Lossless zoom: Pixels within pixels
Of course, bringing us right up to date is the Nokia Lumia 1020′s astonishing lossless zoom. Digital zoom has taken a significant bashing over the years – and mostly for entirely justifiable reasons. But the capability of the 1020 being able to take 38 megapixel photo means that you can digitally zoom in and lose nothing in the quality of the image. It’s a knock out feature without the cumbersome hassle of lugging around a massive lens. We think it will forever change the way we take photos with our smartphones, but what about you? Let us know your opinion of Lumia 1020′s zoom in the comments below.