I’ve given #traveltuesday the day off…again, as I attempt to re-orient my schedule of “day themes” for this blog. Who knows, I may just toss the whole concept out completely?
Today’s Post by Joe Farace
“When you’re shooting with long lenses, even if you’re shooting a close-up, you feel the air, the distance between the camera and the subject.”—Emmanuel Lubezki
A teleconverter aka tele extender is a secondary lens that’ can be mounted between a camera body and a lens to enlarge the central part of a captured image to produce greater magnification by increasing the lens’s focal length.—That’s one definition.
A 2X extender doubles the (apparent) focal length of a lens but there’s no free lunch. It also gobbles up light to the tune of two f/stops. This does not necessarily halve the resolution of a digital or film image. This is not necessarily a bad trade but if you put it on a slower—smaller aperture—lens it can cause focusing problems. That’s because many camera’s autofocus systems require a lens aperture of f/8 or less in order to function effectively. So do the math before attaching a 2X extender to a smaller aperture zoom lens and be sure to read your camera manual, as painful as that may be for some of us.
Caveat: Using a teleconverter with an existing lens is usually less expensive than acquiring a separate, longer telephoto lens but as the teleconverter is magnifying the existing image circle, it also magnifies any lens aberrations.
How I Made this Photograph
Having a teleconverter can be useful for macro work because it magnifies the size of small objects, such as this butterfly that I photographed at Denver’s Butterfly Pavilion using a Canon EOS 5D Mark I and an EF 50mm f/2.5 Compact Macro lens with 2X teleconverter attached. The exposure was 1/25 sec at f/14 and ISO 400 with an (expensive) Canon MR-14 EX II ringlight used as a light source. If a ring light is something you may only use occasionally, I’ve been told—but don’t personally know, I haven’t tried one—that the YONGNUO YN-14EX TTL Macro Ring Flash does a similar job at considerably less cost. (Caveat: I don’t know what the effect of tariffs might have on that price.)
There may be times when you don’t need a 2x lens conversion and other times when you just can’t afford the two stops of light loss. That’s when you may prefer to use a 1.4x teleconverter that will turn a 300mm lens into 420mm but only decreases the maximum lens aperture by one f/stop. Tip: Having two teleconverters in your camera bags triples the number of focal lengths that you have available and the prices ($399 for Sigma 2X models) for these devices, depending on your financial frame of reference, may represent an optical bargain.
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