Product Description

This extender has been re-designed optically and offers excellent performance with compatible EF lenses (same as the Extender EF 1.4x II). It features a new seven-element design, and same weather-resistant design and anti-reflection internal construction as the new EF 1.4x II. The EF 2x II doubles the focal length of any lens it's mounted to, and reduces its effective aperture by two stops. With the EF 2x II, AF is possible with any EOS body if the lens has an f/2.8 or faster maximum aperture, and compatible Image Stabilization lenses maintain the IS feature when used with any current EOS camera.

Product Details

• Brand: Canon
• Model: 6864A004
• Dimensions: 3.50" h x 3.80" w x 5.30" l, .58 pounds

Features

• Telephoto extender designed to double Canon EF lens focal length
• Ideal for shooting close-ups from a distance at sporting events
• Weather-resistant and anti-reflective internal construction
• Maintains autofocus with any EOD body with f/2.8 or faster aperture
• Measures 2.8 inches in diameter and 2.3 inches long; weighs 9.3 ounces

Amazon.com Product Description
Designed to double the focal length of any compatible Canon EF lens, the Canon EF 2x II extender telephoto accessory is ideal for sporting events and nature photography. The lens boasts a new seven-element design, along with the same weather-resistant and anti-reflective internal construction as the companion EF 1.4x II extender. More significantly, the extender supports autofocus with any EOS body provided the lens has an f/2.8 or faster maximum aperture (the EF 2x II reduces effective aperture by two stops). The EF 2x II--which also maintains an EOS camera's Image Stabilization technology--carries a one-year warranty.

• Magnification: 2.0x
• Lens construction: 7 elements in 5 groups
• Dimensions: 2.8 inches in diameter and 2.3 inches long
• Weight: 9.3 ounces

Customer Reviews

Must have
If you need more zoom, this is the item. If you have a lens larger than f2
beware, do some reading. Otherwise must have.

Compatibility
This extender is not compatible with the Canon EF-S 18-200mm f/3.5-5.6 IS. The Canon web site and this site leads you to believe that it is compatible. Granted the 18-200 is a new lense, but none of the compatibility charts address this lense/extender combination. I had to return the product.

Autofocus does not work with XTi body!
I did not find any information regarding the incompability between the Extender and my XTi body. According to email received from canon it really do not work.
Be careful before you buy it!