what does a telextender do?

multiply the amount by which you can zoom?

Hi,
what ever the value of the extender is, is what you times the lens. i.e. the stock 16X 5.5mm-88mmIS XL-1 lens with a 1.6 extender is close to 1000m ( in35mm equivalence) If you were talking just plain 35mm lenses a 50mm lens with a 2 x extender wwould be 100mm.

Bruce

Bruce is correct. The math works out like this: 5.5mm-88mm zoom multiplied by 1.6 gives us a 8.8mm-140.8mm zoom lens. The 35mm film equivalant can be obtained by multplying those result by 7.2 (63mm-1014mm). This yields a magnification of a little over 20x at maximum zoom (1014 divided by 50). But, like all things in photography and video, the gain comes at a price. You will loose a little over 1 stop of light. A 2x extender losses 2 stops of light.

Jeff

cheers guys

Thank you Jeff,
you put it much more elloquently and informative thanI. I was not sure about the exact f/stop loss,but I thought he'd figure that part out.

Thanks again