Help! I’m going on a safari next week! Which telephoto lens should I get?
The ExposureWorks Introduction to Telephoto Lenses
What is a telephoto lens?
Obviously, it’s that big lens. The one that brings things close. Magnifies subjects in the viewfinder. Has a long focal length and a narrow field-of-view.
What are they for?
We use telephoto lenses whenever we cannot get close enough to our subjects either for practical physical or social reasons. Whether it is the Sun, the Moon; a lion or a bald eagle; the Superbowl or a wedding there are plenty of occasions when you can’t stand next to your subject.
Range v. Aperture
Nowhere is the photographer’s dilemma between having a preference for range or aperture is more painfully obvious than with telephoto lenses. My recommendation, as always, is that you decide on your budget first. It’s never a problem to buy a more expensive lens and then an even more expensive one. But don’t forget: it’s not the lens taking the picture, but you. Reading this article, think about the combination of zoom range and aperture that you’d like and then go through all your options: your brand’s own, new lenses, second-hand ones, and new and used third-party optics. Chances are, you’ll be able to get the lens that you really need (which may not be the one you want) for an affordable price!
Only telephoto primes and the best zooms have this large a maximum aperture. Nikon, Canon, Sigma all make f/2.8 70-200mm (sometimes 80-200mm) zoom lenses. They also offer outstanding 200mm and 300mm primes but these lenses are usually attractive to professionals only – as most photographers will prefer the flexibility offered by zooms.
A few lenses stand out of the crowd with their range and aperture. Sigma makes both an f/2.8 120-300mm lens and an astonishing f/2.8 200-500mm one. While the former is perfectly affordable (albeit not cheap) lens, the latter is more an item to be admired at trade shows than a viable (or even practical) alternative.
Do I need to get one of these for my safari?
No. Not unless you’re a dedicated wildlife and sports photographer. Not unless you plan on shooting a lot in low light or indoors. These lenses are beautiful, exceptional quality beasts but if you’re on a budget (and who isn’t) and you know that most of your photography will be in the daytime, you can get away with a smaller aperture.
These lenses offer a great compromise. Their maximum apertures are still quite large, they are only one stop slower than their big brothers (or sisters). However, exactly because of this, they cost a lot less. (There are many old, manual focus zoom lenses still out there that are f/4.)
Modern lenses offering advanced image stabilization (VR – Vibration Reduction in Nikonspeak, IS in Canonspeak) aim to balance this one-stop loss of light with the ability to get acceptably handshake-free shots even at slower shutter speeds. Naturally, you may choose instead to raise your ISO by one stop and with most current DSLRs the increase in noise may not be severe.
Variable aperture zooms – life somewhere between f/4 and f/6.3
For those on a photographic shoestring or looking for something a lot more compact and lightweight, these lenses are the obvious choices. Their limited apertures are still perfectly fine for daytime photography and the optical performance ranges from decent to excellent. You should consider the zoom range: some go from 70-300mm offering great flexibility.
Manufacturers, however, are always coming up with new lenses and some of these are indeed very exciting alternatives. Canon has an f/4.5-5.6 100-400mm lens and Nikon makes a similar f/4.5-5.6 80-400mm one. Sigma manufactures an f/5-6.3 150-500mm zoom. These lenses offer such outstanding range that many wildlife photographers may opt for them.
Brand new the first two cost around £1000, while the Sigma lens is currently under £500.
Teleconverters – increasing the focal length of your lens
Teleconverters (or extenders) turn your lens into even more of a telephoto lens. They come in various ‘strengths’: the multiplying factor can be 1.4x, 1.7x or 2x. They are a great way to increase your available range without buying another lens. A 1.4x extender will turn your 70-200mm zoom into 100-280mm lens, a 2x converter into a 140-400mm lens.
So where’s the catch?
First, in a noticeable loss optical quality. After all, you are putting two lenses one after the other and although both might be manufactured to an exceptionally high standard, the combination will always result in losses.
Second, a loss of aperture. The extender’s multiplying factor applies not only to your focal length, but also to your aperture. A 1.4x teleconverter gives you 1 stop less light, a 2x extender 2 stops less.
In practise these wonderful little gadgets make sense only for f/2.8 or at most, f/4 lenses. A 1.4x extender will turn these lenses into f/4 and f/5.6 lenses respectively, a 2x one into f/5.6 and f/8 lenses.