teleconverter

[rosco1971]

i would like to know if anyone has used a sigma 1.4 ex teleconverter with a canon L lens 70-200 f2.8 and did you lose any significant sharpness of image quality.

[tim]

Start here: http://photography-on-the.net/forum/showthread.php?t=41922 , then do a search. There have been posts about this that might help you out.

[Citizensmith]

Yes you will loose sharpness. Whether it is significant will depend on the subject and your own personal standards. Most likely though it'll be acceptable.