2x tele lens converter?

[gokenin]

I was wondering if anyone uses a converter I saw one on ebay http://cgi.ebay.com/2X-TELE-LENS-CO...yZ106876QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
and was thinking that this would be a cheaper way to increase my lens length without having to buy another longer lens? I am thinking of getting it to use with my 50-200 lens if i understand things correctly this would make it the equvilant of a 100-400mm? any recommendations

 

[gruZ]

I can't speak to the one you've linked - but I owned a Sigma 2x for about a year, and generally wasn't that pleased with it. I used it with a Sigma 70-200 F2.8, which is a very sharp lens, and the tele reduced the sharpness by a noticeable amount. Also, you'll lose a full 2 stops when using a 2x tele-converter.

If I were to purchase one again, I would buy a 1.4x, as you only lose one stop, and from all the reviews I've read, the images are much sharper than a 2x. Just my .02

 

[Code]

2x teleconverters are only for very fast lenses. The Pentax 50-200 is f/4-5.6, and a 2 stop loss would make it f/8-11 .. it would not be able to autofocus, and wouldn't be of much use anyway if it could.

 

[deletedpenguin]

I bought a Canon 2X, and my images suffered greatly. I returned it and bought a 1.4X and couldn't be happier. 2X just degrade your pictures way too much to make it worth while (and this was on a 70-200f/2.8L lens). 1.4X stacks nicely.