The questions: Can sharp images be consistently obtained with a long lens and a 2.0 teleconverter? Does autofocus work with such a setup? And what about losing two full stops of light?
Dissuaded by some of the lackluster – even negative – reviews for Nikon’s TC-20III teleconverter in particular and for 2.0 teleconverters in general, I put off adding one to my gear bag for quite a while.
Claiming that the TC-20III teleconverter only works with lenses with an aperture of 2.8 or greater, one reviewer states: “…(I)f you have an f/4.0 lens, forget about autofocus – you will have to resort to manual focus.” Another reviewer seconded this opinion, claiming that “(The TC-20III) only works well if you start off with an f/2 or f/2.8 lens…” This same reviewer went on to opine that, “2x teleconverters have always been too much. They’ve robbed too much sharpness, and made autofocus poor. I’m not a fan of 2x teleconverters. 1.4x ,and maybe 1.7x converters give much better results, but since they offer negligible extra magnification, why bother?”
There are a lot of reasons to “bother” with teleconverters, as just about any serious wildlife photographer knows. Consider, as an example, a 200mm lens. Adding a 1.4x teleconverter means that you’ve increased the lens’s reach by a factor of 1.4, thus converting it to a 280mm lens. (1.4 x 200mm = 280mm). Take that same 200mm lens and add a 2.0 teleconverter, and you’ve doubled the lens’s reach to 400mm. (2.0 x 200mm = 400mm). Like a pair of binoculars, this extra reach brings wildlife closer and can often mean the difference between no shot, a poor shot and a great shot. So, while teleconverters may not have much application for portrait, landscape and studio photography, they can be game-changers in the world of wildlife photography. Meanwhile, it never ceases to amaze me how some people with some modest amount of expertise in one niche of their hobby or profession think nothing of making wildly inaccurate blanket statements based on their own limited experiences.
For the past week, I’ve been shooting almost exclusively with Nikon’s AF-S Nikkor 600mm f/4E FL ED VR lens coupled with Nikon’s TC-20III teleconverter. I didn’t know what to expect. Here’s what I discovered:
1. In most conditions, losing two full stops of light – meaning that wide open the aperture is at f/8 instead of f/4 – isn’t as big a deal as I thought it would be. With quality DSLRs, the ISO can be pushed up to 2000 or even slightly higher without introducing too much noise into the picture. That means you can still shoot with a fast enough shutter speed to, for example, freeze a pair of mallards in flight in soft morning light. (See above photo.)
2. While autofocus works less efficiently, it still works well and, in most situations, is a much better option than manually focusing. At times it seemed like the “brains” of this system had trouble keeping up. The lens had a harder time finding the subject, especially if it was small or if the background and surroundings were busy – such as when shooting birds in bushes. Capturing birds in flight was particularly challenging. At one point while I was out on the ice on Chignik Lake, a Common Merganser that was fairly close caught a stickleback. As it repositioned the fish to swallow it head first, it gave me opportunities for captures of this dynamic moment. I had to remind myself that patience with the lens, rather than swearing at it, would probably be the better course as I attempted to focus on the bird while the “confused” lens searched and searched. However, I did get two good frames. One is above. In the other, the stickleback’s three spines can clearly be counted.
3. Shooting at f/8 and even at f/11 I could still achieve a nice background canvas of bokeh. I was concerned that with the aperture stopped down, I wouldn’t be able to get the kind of agreeably blurry background necessary to, for example, allow a pair of colorful Pine Grosbeaks to stand out from the background of winter-brown willows and alders where they typically feed. What I hadn’t fully appreciated was that with a reach of 1200mm (2.0 x 600mm), it would be fairly easy in most circumstances to “clean up” the background.
4. The reason I added a 2.0 teleconverter to my gear comes down to one word: Reach. There are certain species of wild animals that are extremely difficult, if not impossible, to capture without serious magnification. But with a solid tripod, a camera that can handle high ISO values, patience and an understanding of your gear and the species you’re seeking to photograph, frames that otherwise would have been unobtainable can be in reach.
Final recommendation: Lenses vary. So do 2.0 teleconverters. So I can’t make a blanket statement. What I can say is that as I did my own research on 2.0 teleconverters, I discovered that some of National Geographic’s top wildlife photographers have, for years, regularly been using 2.0 teleconverters. Joel Sartore includes them in his Nikon-based gear bag; Tim Laman utilizes them as part of his Canon-based gear bag. So, whether your subject is monkeys in a rainforest canopy, Tundra Swans on an Arctic lake, or a sleeping owl you don’t want to disturb, 2.0 teleconverters can give you the extra distance necessary to get really special captures.
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