I (stupidly) sold my top of the line Sony 1.7x teleconverter last year and now wish I hadn't. Now I'm looking for a replacement. Any recommendations for a sub $200 teleconverter?

And while I'm at it, why do all teleconverters have vignettting at the lower end of the zoom range? No one makes one without vignetting, so it must be very hard / very expensive, but I don't understand the optical physics well enough for it to make sense.

It is very expensive to prevent vignetting and the designers of these devices know that the price/performance would be poor and cause very poor sales.

So they make them perform only at the highest tele settings since that's where, presumably, people want the boost anyway.

Mike's right. You buy a tele-converter to extend your telephoto reach, and if you shoot at mid zoom you'll get much better quality pictures if you take it off. They could make a tele-converter that disn't vignette as you zoomed back, but the front element would be huge, the thing would weigh as much as a dog and it would cost a wallop of dosh. You wouldn't like the look of it and you sure wouldn't like the price.

Making wide-angle converters that don't vignertte throughout the zoom range is a lot easier.

tom.