Cameras come in all shapes and sizes, some zoom some don’t – but there seems to be a misconception that a zoom is just for one thing “getting closer to the action”, it’s not. Using the right zoom lens can dramatically change the picture, but first I think I need to just touch on a few terms
Explanation of a few terms…
A ‘zoom’ lens is a lens which can change its focal length, focal length (to put it simply) is how much it magnifies the image – if you “zoom in” you increase the focal length, “zoom out” decreases it, a wide angle has a low focal length and a telephoto has a high focal length.
So why is focal length important, and why did professionals prefer not to have zoom lenses?
Zoom lenses aren’t favoured by professionals too much, instead they prefer having a few “prime lenses” which don’t zoom – they typically are better quality and have higher “aperture”, but for most of us taking half multiple lenses with us isn’t really an option, and the quality of budget optics is often ‘up to the task’.
Focal length impacts on “depth of field” and also how dynamic an image is.
Longer focal lengths = less in focus (only the point you focus in will be sharp)
Shorter focal lengths = more in focus and more dynamic (3 dimensional) the image seems
It is also common for shorter focal lengths to distort the edges of an image, giving a curved and almost stretched effect. This isn’t usually noticeable if you’re going for a large panoramic skyline or street view, but can provide unwelcome changes to a close up subject.
Because of this, portraits typically look better with longer focal lengths, particularly if your subject has an unusually big nose, and landscapes look better with wider (smaller) focal lengths.
So for most people they want a zoom range, not just to get a bit closer to the action but also to impact the look of the photo itself, this is something a digital zoom or a touch up afterwards in Photoshop isn’t truly able to do.
So what do the numbers mean
There are two numbers that are used when describing lenses, and these seem to vary according to who is talking about it and the nature of the camera, it needs to be noted that the numbers will change according to the format, and digital and “film” cameras numbers aren’t quite the same.
Focal Length
24 or less = extreme wide, down to “fish eye”
28 – 35 = wide angle
35 = 70 = “standard” focal length
70+ = telephoto
3 X or some other number X zoom
Found when describing the majority of compact, or fixed lens cameras for the average consumer market, this is a measurement of how many times you can zoom in – a camera or lens that can zoom in from 20 to 100 would be a 5x zoom (5x20=100) common numbers at the moment are 3x, 5x all the way up to 12x zoom (sometimes even more). The bigger the number, the more you can probably zoom in.
It has to be stated that anything over than 12, is frankly a lot and you may find the quality of the camera is questionable at this point, it’s also wise if you do have a “long zoom” to make sure that you use it with good light or a suitable tripod / support.
Written by Gerry White
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