Marnie, The general rule of thumb is that teleconverters work best when the lens is quite high optical quality and relatively fast (4.0 or faster). That usually leaves out most of the zooms. The one exception is the pro grade 80-200's. They can be used on any lens, but you have to watch out for loss of speed, loss of AF (due to speed loss), image degradation, vignetting, contrast loss, etc.
Sometimes a manufacturer will make a "matched" converter for a particular lens (even zooms). These usually work quite well. -- Best regards, Bruce Monday, February 7, 2005, 8:51:49 PM, you wrote: Eac> In a message dated 2/7/2005 6:09:50 PM Pacific Standard Time, Eac> [EMAIL PROTECTED] writes: >> I suggest considering a 1.4x. One of those will give better >> results than >> a 2x. Eac> Thanks for all the great input, everyone! I want to do some more research, Eac> but I'm starting to lean towards a 7-element Kenko. I think when I get my D Eac> back from the shop, I might buy the 1.4x and the 2x and test them both with Eac> the zoom I plan to use them with. I'm going to ask around but my lens might Eac> be too new for anyone to have tested it much. Eac> Thanks, Eac> Amita Eac> ======= Eac> Just a general sort of question to anyone willing to answer. Eac> I have mainly zooms. It's sort of useless exercise in futility to put a Eac> teleconverter on a zoom, right? Or not? Eac> Marnie aka Doe
