Photo courtesy of Nikon The lens: a photographer's most crucial piece of kit. That is, so long as he can properly operate his camera body - as discussed in my write-up on choosing the right camera body for safari.
Weight limits are often a constraining factor on the puddle jumpers you'll likely be boarding en route to wildlife photography destinations, and glass isn't light. There is no 'right' set of lenses to pack in your bag, but every photographer will be better served by an informed and well-condsidered selection of the glass at their disposal. When deciding which pieces of glass to haul with you across the ocean you ought to know their capabilities and limitations well. In the world of lenses some absolutes hold true across the board while other factors depend on each photographer's unique vision the types of images he hopes to capture.
First off, a few basics; the essential defining characteristics of all lenses are focal length and maximum aperture
As I mentioned in a prior blog post, photographers typically elect to tote two camera bodies with them on safari in order to have quick access to a wide range of focal lengths. Changing lenses in the field can result in both missed shots and dusty sensors, so if you can afford to you should strongly consider bringing two camera bodies with you on your photographic safari.
When most people think 'safari lens' they conjure up an image of an 8-pound, 2-foot-long telephoto behemoth. Because long telephoto lenses allow us to convey a sense of closeness with far away subjects - and animals often won't allow us to get close - they are the go-to lens for many wildlife photographers (and will likely be the most important lens in your wildlife kit). But telephotos aren't the only suitable lenses for wildlife photography. In fact, everyone should have a standard and/or wide angle lens in their bag on safari. Animals sometimes get close enough - or allow us to come close enough - to fill the frame with a standard lens or create an interesting perspective using a wide angle lens. Once a leopard walked right up to our vehicle and passed under its rear bumper. Another time a rhino charged our vehicle, coming feet away from tearing off the rear bumper. And it's not uncommon to come within 20 feet of a 12-foot-tall, 10,000 lb elephant; opportunities and compositional possibilities are endless. But even if you're keeping your distance, large animals like elephants and giraffes fill a frame nicely at shorter focal lengths. Nick Brandt, for example, shoots almost exclusively with standard lenses (in order to convey depth and avoid the telephoto compression mentioned earlier) and has created some stunning results.
Also mentioned in a prior blog post, the field of view and depth of field attained at a certain focal length will depend on the size of your camera's sensor. All factors held equal, full frame (35mm) sensors produce a wider field of view and shorter depth of field than do crop (APS-C) sensors. This is a very important factor to consider then selecting equipment that is appropriate for you and your budget. Not only do crop cameras tend to cost less, but they magnify the effects of a telephoto lens. For example, a 400mm lens becomes a 600mm equivalent. Generally speaking, the longer the lens the bigger the price tag, and using a crop camera is a common strategy to achieve longer effective focal lengths.
Teleconverters are another method of eeking out more distance from a telephoto lens. These small elements that fit between the camera body and lens do just as the name implies - multiply (or convert) the focal lengths of telephoto lenses. On first though using a tiny teleconverter to amplify the zoom of a cheaper, smaller lens to achieve the effect of a larger, more expensive one sounds like a no-brainer, but these little devices do come with their caveats. First, only fairly hefty (and expensive) lenses are able to accept teleconverters in the first place (think 70-200 f/2.8, 300 f/2.8, 200-400 f/4, and the likes). Second, teleconverters reduce the maximum aperture of your pricey glass by one stop; this turns a f/2.8 lens into a f/4 and a f/4 lens into a f/5.6. Third, teleconverters inhibit the metering and autofocusing functions of your camera; the degree to which this phenomenon occurs, however, will depend on the combination used (do your research first). In order to reduce compatibility issues, be sure to only use teleconverters made the same brand as your lenses. Finally, teleconverters tend to slightly reduce image quality. So while you do get more bang for your buck with a teleconverter, it does come with trade offs. All things considered, I believe it's worth having one in your bag.
Speaking of bang for your buck, prime lenses (fixed focal length) will always deliver superior results to zooms per dollar spent. As a general rule, prime lenses are sharper than comparable zooms. You also typically gain a few stops of light (larger maximum aperture) with primes. What you lose is versatility. I can't tell you which route is right for you, but it's generally prudent to have at least one prime in your bag.
A few specs worth paying attention to when shopping for wildlife lenses:
Below are a few lenses I recommend Nikon full frame (FX) shooters consider when selecting lenses for their safari kit. Canon makes comparable lenses across the spectrum, which can be found easily. I generally recommend that you steer clear of third party lenses unless you're considering high quality brands such as Zeiss or Sigma.
If money is tight...
If money isn't an issue...
* Nikon d lenses will only work with high end bodies containing a manual focusing screw
** Steer clear of the VRI version of these lenses
That's all for this time - be sure to leave your questions and comments below!