Learning About Teleconverters
A teleconverter is an auxiliary lens that goes between the camera and the lens. It increases the effective focal length of a telephoto lens. Choose 1.4x, 1.7x, and 2x teleconverters from a wide range of manufacturers. Also known as extenders, these lenses open exciting possibilities for photographing distant objects, such as capturing the moon, bringing sports action close up to your lens, and taking pictures of elusive wildlife.
OEM and Third-Party 2x Teleconverters
Not all teleconverters will work with all lenses. For example, OEM Canon teleconverters only work with EF L series telephoto lenses, Tamron teleconverters work best with certain Tamron telephoto lenses, and Sony E-mount teleconverters with specific G Master lenses. Also, lenses with protruding rear elements, like some wide-angle and macro lenses, will not work with a converter. Check the manufacturer's recommendations.
Light Loss Through Teleconverters
When you add a converter, the amount of light your camera sensor receives is reduced. A 1.4x converter reduces light by one stop, and a 2x converter by two stops. At the same time, the effective focal length increases, so you need higher shutter speeds to prevent camera shake. Generally, the shutter speed should be higher than the reciprocal of the lens' focal length. To calculate this, multiply the lens focal length by the teleconverter ratio and also by the crop factor, if you're using a cropped sensor camera. Here's an example: A 300mm lens with a 1.4 extender on a 1.6 cropped sensor camera has an effective focal length of 672mm, making the minimum shutter speed be 1/750 second.
You can compensate for the loss of light from the extender by using a steady tripod, increasing your ISO, using the widest aperture possible, or shooting in good light.
Alternatives to Teleconverters
While a teleconverter is a cost-effective solution for when you need a longer lens, other solutions are available. These include camera add-on lenses for fixed-lens cameras, and smaller kit lenses that achieve similar results. These add-on accessories screw on to the front of the lenses. Another idea is to use camera T-mount adapters to convert telescopes or T-mount lenses into telephoto lenses. This is a solution chosen by many amateur astronomers. Finally, you can breathe new life into old telephoto lenses with lens mount adapters.
Extend the reach of your favorite telephoto lens with a teleconverter. Choose from the wide range of extenders at B&H Photo and Video.