Telephotos on test
Find your next telephoto lens with our in-depth group test
With prices ranging from abut £100 to £400, budget 70-300mm lenses can be a movable feast, especially in terms of physical length and aperture. Indeed, as you move through the zoom range, these lenses stretch considerably in length, while the widest available aperture tends to shrink from f/4 to a fairly narrow f/5.6. To keep shutter speeds fairly fast for minimising camera-shake and motion blur, you can often find yourself having to combine the longest zoom setting with the widest aperture, which can really degrade image sharpness.
At the other end of the scale, fully professional telephoto zooms like the Canon EF 70-200mm f/2.8 L IS II USM, the Nikon AF-S 70-200mm f/2.8G ED VR II and the Sony 70-200mm f/2.8 G SSM II are much more refined. The relatively wide f/2.8 aperture remains available throughout the zoom range, and the physical dimensions of the lenses remain fixed at all zoom and focus settings. However, they can be heavyweights in two undesirable ways. First, hefty price tags of nearly £2,000 for the Canon and £2,500 for the Sony put them beyond the reach of many photographers who aren’t taking pictures for a living. Second, with their large front elements to enable an f/2.8 aperture, they have a big, heavy build, typically weighing in at around 1.5kg.
A popular compromise is to opt for a 70-200mm f/4 telephoto zoom, usually costing less than £1,000. These lenses are compact and weigh less, yet still tend to have robust build quality and premium-grade glass. They also boast a constant-aperture
“Compared with f/2.8 lenses from Canon and Nikon, competitors from Sigma and Tamron cost half”
design, albeit at one f/stop narrower than their f/2.8 counterparts.
That’s less of a problem than it used to be. The latest SLRs usually deliver excellent image quality at raised ISO settings, putting less of a priority on ‘fast glass’. You can also get a tight depth of field when shooting at 200mm at f/4.
Another bonus for Canon and Nikon shooters is that some of the latest SLRs can autofocus when the widest available aperture is as small as f/8. This means you can fit a compatible 2x tele-converter to a 70-200mm f/4 lens without having to resort to manual focussing. Live View focussing is also possible at even narrower apertures but, on SLRs at least, it tends to be very slow.
Switching brands
Another way to reduce purchase costs is to switch brands. Compared with 70-200mm f/2.8 lenses from the likes of Canon, Nikon and Sony, direct competitors from Sigma and Tamron often cost half the price or less. Even so, they still offer a very good standard of build quality, upmarket optical elements, and similar ringtype ultrasonic autofocus systems, as used on own-brand telephotos. The latter can be an important consideration, because many of us use this type of lens for sports, action and wildlife photography, where fast, accurate autofocus is vital.
The Panasonic Micro Four Thirds and Sony E-mount lenses are the only ones in this group test to lack ring-type ultrasonic autofocus. Instead, they use stepping motors. (Canon SLR users with the latest
18-55mm or 18-135mm kit lenses will be familiar with this technology.)
A plus point for video shooting is that this autofocus technology is practically silent, while also giving smooth focus transitions without the lurching effect of conventional systems. The downside is that, in SLR lenses at least, autofocus isn’t particularly quick. In our tests, we’ll see just how the autofocus performance of the Panasonic and Sony lenses measures up.
For hand-held telephoto shooting, image stabilisation is another key factor. At long focal lengths, we’ve generally found that in-lens optical stabilisation is more effective than camera-based, sensor-shift stabilisation. Indeed, Canon and Nikon SLRs, as well as Sony’s current E-mount bodies, don’t have in-camera stabilisation anyway.
Prime concern
Naturally, zoom lenses aren’t the only option. At any given price point, prime telephoto lenses often offer wider available apertures, a more compact build, and better overall image quality. The Pentax DA* 200mm is certainly one of the smaller lenses in this test group – and the least expensive, despite having a wide f/2.8 aperture. By contrast, the Sigma APO 180mm prime is the heaviest and most expensive lens in the group. However, it’s a dual-purpose telephoto and macro lens, delivering full 1.0x magnification at its shortest focus distance.
Getting back to the greater convenience and versatility of zoom lenses, 70-200mm is the most popular telephoto range, at least for constant-aperture designs. All five 70-200mm lenses featured in this test group are compatible with full-frame sensors. Being a Micro Four Thirds lens with a 2x focallength multiplier (or crop factor), the Panasonic 35-100mm has the same effective range as the other zoom lenses when they’re mounted on full-frame bodies.
However, when using 70-200mm lenses on cameras with APS-C sensors, you get a boost in effective reach. This is usually 1.5x for most APS-C format cameras, and 1.6x for Canon bodies, resulting in effective zoom ranges of 105-300mm or 112-320mm respectively.