On this video, photographer Tony Northrup looks at teleconverters, how they effect our lenses and image quality and what their advantages and disadvantages.
Teleconverters are optical components which can help us extend the reach of our lenses. Typically teleconverters come in 2 magnifications – 1.4x and 2x (some others also exist like 1.7x). Using a 1.4x teleconverter on a 400 f/4 lens for example will give you an effective focal length of 560mm but will also reduce your aperture to f/5.6.
Northrup also interestingly claims in this video that using a teleconverter on APS-C cameras will typically not give you any observable image quality benefits (and basically all you get is just a magnified image but not more details – this is interesting and something that we would certainly like to test ourselves when we have a chance).
In the past Larry Becker from Kelby mentioned teleconverters briefly in the 3’rd part of the Ultimate Beginners Guide to Lenses but Northrup’s video is the first one that we publish here which looks into the real advantages and disadvantages of using teleconverters.