About the Photographer
Adding a teleconverter (TC) or extender (Ext.) to a lens, either to increase the reach of a telephoto (TC), or to increase the magnification of a macro lens (Ext.), always results in a corresponding loss of image quality. The user is, quite literally, exchanging ‘quality’ (best resolution) for ‘quantity’ (more reach/magnification). Sometimes this is quite noticeable, removing the benefit; however, with judicious selection, sometimes the results can be quite good. Therefore, I try to be judicious in my usage of both TCs and extenders, preferring not to use them … unless I feel the trade-off will actually improve my result, rather than compromise it. That said, here is what I utilize:
Unlike a teleconverter (or TC), which actually has internal glass that magnifies your existing lens, an extension tube is hollow. This creates space between the lens and the camera, which allows you to come closer than usual, to small subjects, thus producing a kind of ‘vicarious magnification’ that such closer proximity allows. Typically, while TCs are used on telephoto lenses (to increase focal length), extension tubes are used on ‘normal’ lenses (to turn them into makeshift macro lenses)—or on existing macro lenses (to increase macro magnification even further). Truth be told, I seldom use extension tubes, as I have many macro lenses, with varying degrees of magnification, but they do come in handy sometimes when I don’t have a proper macro lens with me. The Kenko set of extension tubes has long been the best value in the industry, and they come in various widths to allow of various magnification increases. They can be used singly, all-together, or in various combinations, in order to achieve various magnification bonuses.
Find on Ebay: Kenko Auto Extension Tube Set DG
Nikon’s upgraded AF-S 2x Teleconverter, the TC-20E III, allows me to double my focal length, while still retaining decent (in some cases, excellent) optical quality. When placed on my 300mm f/4E PF, attached to my D500 (which offers an additional APS-C 1.5x “crop factor”), I am able to achieve an overall ~900mm f/8 equivalent focal length that is hand-holdable all day. Even better, this TC also increases my macro magnification potential as well, from 1:4 (.25x) to 1:2 (.5x). However, in some contexts, this 2x TC can cause unacceptable image quality reduction and it can also render my AF useless in low-light conditions. However, when used judiciously, and in adequate light, this TC can give excellent results and provide a major “reach” advantage, without weighing me down.
See @ Nikon: Nikon AF-S 2x Teleconverter TC-20E III
Nikon’s upgraded AF-S 1.4x Teleconverter, the TC-14E III, is an excellent way in which to increase focal length, while still retaining excellent optical quality. This TC is pretty much glued to my 300mm f/4E PF, where when combined with my APS-C D500 camera (which offers an additional 1.5x DX “crop factor”), I am able to achieve an overall ~630mm f/5.6 equivalent focal length. Even better, the TC also increases my macro magnification potential from 1:4 (.25x) to 1:3 (.33x). Both amplifications offer tremendous field benefits with only a negligible amount of image quality reduction. I have repeatedly and consistently found this lil’ teleconverter to be an indispensable tool for my hiking.
See @ Nikon: Nikon AF-S 1.4x Teleconverter TC-14E III
This teleconverter only comes with the Nikkor 800mm f/5.6E FL ED lens, and is specifically calibrated for it, creating a “1000mm f/7.1” reach in the process, while maintaining optimal sharpness. All this sounds exciting, and has its applications, but I tend not to use it much. For one thing, in low light, the f/7.1 aperture makes focusing difficult—and, for another, the f/7.1 aperture itself isn’t typically where I like to be anyway, from a bokeh standpoint. That said, with adequate lighting, even an 800mm lens sometimes doesn’t give me enough reach, and this TC gives me just enough extra “boost” (200mm), without minimizing the image quality too badly.
See @ Nikon: Nikon AF-S 1.25x Teleconverter TC800-1.25E ED