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Photography Question 
Jim L. Knapp
BetterPhoto Member Since: 11/24/2009

2X Lens for Canon Rebel ES

I want to purchase a 2X lens for my Canon Rebel ES 75-300mm lense. What is recommended, and what kind of price am I looking at?

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1/12/2010 10:18:38 AM

Lynn R. Powers   Jim,
Teleconverters degrade the image to some degree. The TE1.4x is not as bad as the 2X. They also reduce the amount of light by one and two f stops, respectively. On my 300mm f4L IS, adding a 1.4X extender would reduce the maximum f stop to f5.6 and the 2X extender to a maximum of f.8.
With that lens, the 1.4X image is still very good but with the 2X is only usable(maybe).
Your camera and most cameras, the Canon 1D & 1Ds and probably the Nikon D3X and D3s being exceptions, will not autofocus at f stops smaller than f5.6. Manual focusing is necessary, which generally means a tripod is also needed. I have seen very high-quality glass, a Canon 500mm f4L with a 1.4X TE, and a 2X TE stacked that came out with excellent photos. Yes, it was manually focused and a high ISO was used.
Your lens is fine as a walk-around general-purpose lens but is not the quality that the prime L lenses have either in build or glass components. When you go to the full zoom of 300mm, your maximum aperture is 5.6. Add a 1.4X and you have a maximum of light of f8 and with a 2X the max is f11. It does get very difficult to focus with an f11 aperture.
If you have your heart set on trying a 2X tele extender I recommend the Kenko MC7DG 2X. It doesn't have the pins telling the camera that there is only an f11 amount of light entering the camera. Your camera will still read f5.6, so it is necessary to do the arithmetic yourself to figure out the proper shutter speed and ISO. My old catalog says it cost $135. It is the better of the two for your purpose with your lens.

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1/13/2010 10:01:15 AM

Jim L. Knapp
BetterPhoto Member Since: 11/24/2009

Thanks for your very informative response to my teleconverter quuestion. I found your response was very helpfull, and thanks for preventing me to make another big mistake.

Jim knapp

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1/13/2010 5:33:28 PM

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