Originally Posted by dighost
I have noticed that some glamour photographers have used 1.4x or 2.0x lens extenders. Is there any advantage to using an extender? My understanding is that the image quality would be degraded by that factor of magnification. Just wondering...
One import reason for using an extender is to avoid the high cost of buying another lens to cover the additional range. I use the Sigma 70-200 F2.8 all the time. That makes it like a 112-320mm on the Canon 20D. Suppose I wanted to shoot something occasionally that needed a 400mm lens. Then rather than buying a whole new lens, I could spend much less money to buy the 1.4x device. Naturally it will not longer allow me to shoot at f2.8, but that will be the biggest drawback. The quality of many of these 1.4 and 2.x items is such that there is little degradation of the image (at least that's what I've found in my use of such devices). Now if you ask this same question at a salesman at a camera shop, they may give you a different answer (why do you think they might do that?).