Tele-Extenders - How To Use Them and What to Expect

I like to keep the Technique Tuesday posts mostly to technique and this one fits the bill. Have you ever thought about getting a Tele-Extender - sometimes called "tele-converters" for your camera. It's a piece of gear that fits between your camera and telephoto lens. It's purpose is to increase the focal length of your lens by 1.4x or 2x. That means if I use a 2x Tele-Extender on my 200mm telephoto, I really have a 400mm optic.

Here is what is cool - put the new 400mm lens (with extender) on my Canon 40D and I have in effect a 640mm optic - pretty darn long. What do you give up - with a 2x extender, it's 2 stops of light, so now my F2.8 200mm lens has an effective maximum lens opening of F5.6. Still, that's not not a bad trade off considering the cost of the tele-extender - about $280 at B&H Photo. Check out TheDigitalPhotographyConnection to see Michael Rather's (no relation to Dan) informative tutorial on using Tele-Extenders right here.