If you’re in the market for new zoom lenses then it pays to understand what the differences are and what your money buys you. With that in mind here’s our in-depth guide to getting the best zoom for your money.
When choosing a zoom that’s right for you there are a number of things to take into account. In addition to overall image quality this includes – but is certainly not limited to – such things such as maximum aperture, autofocus speed and performance, the presence of built-in image stabilisation technology, build quality, and size and weight.
Maximum aperture is important for two reasons; first of all, it allows you to create a shallower depth of field, thereby drawing attention to the main in-focus subject; and second, it also allows you to use higher shutter speeds in low light. The second of these could be considered slightly less important these days, thanks to the widespread use of built-in image stabilisation (IS) technology. This aims to compensate for naturally occurring handshake when shooting handheld at slower shutter speeds. Most built-in IS lens technology allows for up to four extra stops of shutter speed.
Autofocus speed and performance is another thing to look out for. Many modern zooms, especially those intended for serious enthusiast or professional use, usually incorporate some form of internal supersonic motor for increased focus-lock speed and silent operation. Build quality is also something to consider; unlike plastic consumer-level zooms, professional-grade lenses tend to be constructed from metal so that they can stand up to the inevitable knocks that occur during daily use. Also, if you need a lens that can be used outside in wet weather then a dust and moisture-sealed sealed zoom is your best bet – expect to pay extra for such luxuries though.
Last but not least, you’ll also need to settle on a focal range that’s right for you. Are you looking to shoot wide-open spaces or get close to your subjects, or are you looking to fill the viewfinder from distance? If you fall into the first category then a wideangle or standard zoom (typically 12-24mm and 24-70mm respectively) is probably the focal range that will suit you best. If, on the other hand, you’re going to be positioned some distance away from your subject and still want to fill the viewfinder then a telephoto zoom (typically 70-200mm) is a better bet.
Zoom lenses – Key features
This is used to control the focal range of the zoom. It’s usually (though not always) positioned in the middle of the lens for easy access and is deeper than the manual focus ring. Many zooms coat the zoom ring in ridged rubber for extra grip.
Manual focus ring
Used to control focus when the lens is in manual focus mode, the MF ring is usually positioned at the front of the lens. On some zoom lenses it
Image Stabilisation switch
A small number of zooms (for example the Olympus 40-150mm reviewed here) use a pull/push AF/MF ring to select focus mode. The vast majority of zoom lenses, however, use a simple switch on the side of the lens.
This is used to switch between autofocus and manual focus modes. Most modern zoom lenses focus internally, so that the front element does not rotate when you twist the MF ring. This makes the use of polarising filters much easier as there’s no need to readjust.
This is where you can most visibly appreciate the overall build-quality of a zoom lens. Consumer-level lenses tend to use plastic lens barrels, whereas the lens barells on pro-grade lenses are constructed from metal.
This is found on the base of the zoom where it attaches to your camera body. Ideally, you want a metal lens mount as this will prolong the life of your lens – especially if you regularly swap in on and off.
The size of the front element varies from zoom lens to zoom lens. As a general rule of thumb, the larger the front element, the better its light gathering capabilities are and the faster it is with regard to its maximum aperture.