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A teleconverter is defined as a second lens that is installed between the primary lens and the
camera. Its main function is to multiply the crucial portion of an image captured by the primary lens itself.
1.4X teleconverters are the most useful and and also offer less distortion. Using a 1.4X teleconverter, a full stop of light is lost. So a 200 f/2.8 turns into a 280mm f/4 equivalent lens. A 100mm f/4 is converted to a equivalent 140mm f/5.6 lens.
2X teleconverters are the most popular and more powerful. Employing a 2× teleconverter (extender or doubler) provides the effect of shooting with lens having twice its
focal length. Subsequently, light Intensity reaching the sensor is also decreased by a 4x factor (and having the effect of increasing the focal ratio) along with the resolution by a 2x factor.
Shooting employing a 2X teleconverter mounted on your camera, a 135mm f/2.8 effectively turns into a 270mm f/5.6 while a 200mm f/4 changes into a somewhat slow equivalent 400mm f/8 . A 50mm f/1.8 ican be transformed to a 100mm f/3.5 employing a 2X. teleconverter
3X teleconverters are seldom used any longer, as they severely degrade images, the effect becomes worse than simply making a smaller image larger.
Teleconverters function much better mounted on a
telephoto lens (over 200mm) than on a shorter focal length lens and predictably work better on a prime lens than on a zoom lens.
The attraction of a teleconverter is to select a 300mm f/4 lens which costs
around $1200) and by only spending an additional $200 you have a 600mm f/8.lens.
Now a 600mm f/4 lens costs more than $7,600 putting it out the grasp of everyone
but the most dedicated wildlife photographers
Teleconverters work pretty much the same as a telephoto lens group of a dedicated telephoto lens. They consist of a array of lenses acting together
as a single deviated lens. The teleconverter is located in such a way that the image created using the objective is situated behind the teleconverter at a distance less than its focal length.
The resulting image is really a virtual entity of the teleconverter that is
subsequently focused further away which result are enlarged. As an example by placing a solitary negative lens so that the resulting image created by the objective being situated half way from the lens and the len's focal point it creates the image from its focal point by enlarging it twice As a result functioning as a 2× teleconverter.
As with any longer focal length lens, shooting using or not using a teleconverter, proper shooting techniques are necessary for crisp images.
Always employ the best lens at hand to obtain the best outcome. Mount your camera, lens and teleconverter on a strong tripod, use the mirror lockup when you can and a remote to decrease any risk of vibration blur.
Kenko Teleplus PRO 300 versions ought to keep their professional caliber sharpness when using better quality telephoto lenses. Although not cheap, you can get one pf these great gadgets for nowhere near the expense of an additional, longer lens; therefore, they become a smart purchase for a value conscious photographer.
Slower lenses
When used with slower lenses they often decrease the effective aperture so much that the autofocus system of the camera ceases to function; depending upon the specific camera system, and may begin from f/5.6 to f/8.
Dedicated teleconverter
Dedicated teleconverters mainly only function with a somewhat limited amount of lenses, normally telephoto lenses of the same brand.
Expense
Using a teleconverter on a lens you already own is less costly than buying an additional, longer telephoto lens, although while the teleconverter magnifies an image circle on hand, it may also amplify any
aberrations present. Teleconverters provide the best results with lenses longer than 50mm or more and are
better when used with
telephoto lenses longer than 100mm to 500mm.
Mar 9, 2011
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