A $10,000, 400mm f/2.8 telephoto lens is awesome, but awesome + sauce is getting that same focal-length reach from a 200mm lens that costs around $800, or even from one that costs $5700. Teleconverters, which are produced by all the major lens manufacturers and by noted secondary makers, mount on your camera to attach your lens for increased telephoto reach. Except for a few exceptions, they enable either a 1.4x or a 2.0x increase in focal length and, depending on manufacturer and model, they range in price from $50 to $600. There are a few teleconverters for medium format systems that are priced significantly higher, but are still commensurate with the costs of their systems.
The obvious advantage of teleconverters, also referred to as “extenders,” is that they extend the reach of your lens and do so at a financial savings compared to buying ultra-telephoto lenses that are normally quite expensive. In addition, they minimize the size and weight of your gear bag. Also, when using a teleconverter, you maintain the minimum focus distance of the original lens, enabling closer focus than would be possible with a longer focal length lens. For someone like me, whose lens budget tops out at about a 70-200mm f/2.8, owning a prime telephoto lens like the Nikon AF-S 400mm f/2.8E FL ED VR, the Sony 500mm f/4 G SSM or the Canon EF 600mm f/4L IS II USM has always been out of the question, but adding a 2.0x extender allows me to shoot sporting events, airshows, and even some wildlife without going into the red. Of course, if I were making my living shooting sports, a fixed maximum aperture ultra-telephoto lens would be a professional necessity, but for an enthusiast shooter, I have the capability to pull subjects close without being forced to choose between my mid-range tele-zoom and a prime ultra-tele lens.
Of course, professional photographers are normally very pragmatic and use teleconverters for the same reasons I do, but also to convert their 600mm lenses into a lens with a 1200mm reach, when the job requires. And alas, there are reasons why pro shooters and well-heeled birders purchase a prime ultra-telephoto and don’t rely solely on extenders; sadly, nothing that we love comes without limitations.
A teleconverter will reduce the amount of light that reaches the sensor, thus decreasing your lens’s maximum aperture by one or two stops. Normally, a 1.4x teleconverter will create a light loss of one stop and a 2.0x teleconverter, a light loss of 2 stops. While this does reduce their efficacy, with the improvement of digital cameras and lenses, including higher ISO standards and image stabilization, the reduction is mitigated. Another aspect of an extender is the obvious fact that you are adding more optical elements between your camera’s sensor and your subject, which can reduce sharpness and even increase aberration. This is an inherent characteristic of a teleconverter that is being improved with each generation, but as mentioned above, and especially when shooting in daylight and with camera support, the benefit of a teleconverter should outweigh these drawbacks.
The other concern with teleconverters has to do with an interruption of the electronic communication between camera and lens, particularly regarding autofocus performance. Proprietary teleconverters made by the same manufacturer as the lens, such as these by Nikon and Canon, and even high-end models by Sigma made for Canon cameras, maintain electronic communication, but in my experience, depending on light availability and chosen aperture settings, autofocus does not always perform as well as it would without an extender in place.
Price and quality are factors that need to be examined carefully when purchasing a teleconverter because there is a wide variety on the market. Even the best extenders should be tested with each of your lenses to determine complete compatibility, but especially when using a teleconverter of the same brand as your lens, you will find that they will expand your creativity and your ability to capture distant subjects without breaking the bank or your back.
Join the conversation! Let us know about your experience with teleconverters, particularly if you have purchased non-proprietary versions.
The “Things We Love” series articles are written by B&H Photo Video Pro Audio staff to talk about products and items that we love. Opinions expressed in the articles are those of the writers and do not represent product endorsements from B&H Photo Video Pro Audio.
