Great accessory for versatile telephoto capability

After receiving the 1.4x Extender, I shot about 600 shots at the San Diego Zoo and Wild Animal Park with the extender on a 70-200mm F2.8L (non-IS) Canon lens and a Canon 10D. I got the extender specifically for this type of shoot, as my previous visits to the zoo with the 70-200 alone didn't quite have the reach that I wanted. With the extender and the 1.6 crop factor of the 10D, the extender gave me almost 450mm, which is pretty amazing for such a relatively compact setup.

The extender was fantastic at the zoo. From 10-50 feet, a typical range for the zoo displays, the coverage with the extender was excellent. I could fill the frame with the animal's eyes when they were close, or have their bodies fill the frame when they were at a distance. It basically eliminated the need to crop any of the properly composed shots afterward, and gave me a focal length that really expanded the composition possibilities.

I have not yet done critical comparisons of side-by-side shots with and without the extender. I'm sure someone has posted such a review on the web. But versus the option of having to heavily crop, the supposed minimal decrease in sharpness or contrast (which can be easily managed in Capture One and Photoshop) is a small price to pay. I personally found the sharpness and detail to be very good.

The extender bumps the f-stop of a 2.8 lens to f/4, which is also a slight sacrifice, but again not a big issue for me given the benefits that the extender offers.

With the extender though, you really have to manage your depth of field with your aperture, as I have several shots where the the depth of field appears to be an inch or two.

Given the simplicity of the extender, there really are no weaknesses that I can comment on, with the exception of removing the extender while shooting. This is by no means the fault of the extender--it is just a byproduct of having a third element to deal with when changing lenses. Removing your lens, then having to remove the extender and put the end-caps back on is a cumbersome process. I suppose with some practice and capping the exposed end of the extender prior to removing it from the lens would make this simpler. Just something to consider so that you don't drop something while making the change.

One nice benefit is that the EXIF information from the Canon camera records the adjusted focal length with the extender. So values such as 98mm and 280mm will appear in the image properties.

One last recommendation when using the extender is to seriously consider Image Stabilized lenses, along with a monopod or tripod. At 450mm, it is very challenging to eliminate motion blur with a non-IS lens. I use a Bogen monopod, which helps alot, but even with a monopod, the slightest movement can cause blur unless you actively manage your shutter speed and keep it above 250. I think an IS lens would help alot, and would be necessary in any type of low lighting, unless you are using a tripod.

It is a relatively expensive accessory, but compared to buying a 400mm lens, it is a bargain when paired with a 70-200 L, and gives you added flexibility with a single lens, rather than toting around an additional heavy telephoto.