Just a quick question I can't find a reliable answer to - is the Canon brand 1.4x teleconverter compatible with the 50mm F/1.8 II lens? If not, does anyone know if any of the 3rd party TCs are? Thanks.

Canon extension tubes are not but I belive the kenko ones are. The canon ones have a piece that juts out where as the kenko tubes have everything contained behind the mount so you can mount glass with no internal cavity on it no problem.

Just a quick question I can't find a reliable answer to - is the Canon brand 1.4x teleconverter compatible with the 50mm F/1.8 II lens? If not, does anyone know if any of the 3rd party TCs are? Thanks.

Simple answer. No. The Kenko will probably fit, but as for it working, that will be a matter of opinion. Teleconverters are not designed to work with short glass like a 50mm. They are really not designed for anything shorter than a 100mm lens. Yes the Canon work on the 70-200, but why would you put one on and then shoot in the 70mm range.

From Kenko's site: The PRO 300 family are designed specifically to be used with prime telephoto lenses of 100mm or above, such as the Tokina AT-X 300 AF PRO, 300 mm f/2.8 lens, and work best with telephoto lenses of 200mm to 500mm. The PRO 300 can be used with telephoto zoom lenses as well as prime lenses. However, Kenko does not recommend them for zoom lenses that have a range starting under 50 mm.

From Sigma's site: Sigma APO Tele Converter 1.4x and 2x are dedicated Tele Converter lenses, which should be used with listed lenses only. Here is the lens list, scroll down for Canon.http://www.sigmaphoto.com/lenses/lenses_tele.asp#canon There is nothing shorter than a 70-200 zoom on the list.

And from Tamron: The SP AF PRO-series teleconverters, with a newly designed optical construction (4-group/5-element for 1.4X and 4-group/7-element for 2X), are designed to be used with lenses that are F/2.8 and of focal lengths of 90mm or greater.

If you are needing something in the 100 mm range take a look at the Canon 100 mm f2.0. It goes for $389.00 at B&H and is a fine piece of glass.

That's what I needed to hear, thanks guys, fantastic as always!