Teleconverter for Sigma lens

[cyber_spud]

I have a Canon 400D and Sigma 70-300mm f/4-5.6 APO DG Macro Lens and I would like to use a teleconverter with it to zoom in closer (should keep me going till I can save up for the Sigma 50-500!) I can't seem to find a teleconverter which is compatible with this lens. The Sigma teleconverter isn't compatible (according to the Sigma website) and neither is the Kenko Pro (emailed the company and they say the Sigma lens will not focus properly with their teleconverter).

Does anyone know of a suitable product please?

[wildlifesnapper]

Hi

I don't think you'll get one that will autofocus.I have a kenko 1.4x and that will autofocus with my 300mm f4 but the 2x is a bit dodgy so I have to use manual focus. My sigma EX 1.4 and 2x will not autofocus with any of my lenses , even my 500mm f4.5.
The kenko should work on your lens but only in manual focus.

neil

[John D]

Hi, As long as the aperature with TC attached doesn't exceed f 5.6 there should be no problem.
I have the Sigma 100-300 f4 EX APO DG lens and an EX 1.4tc and auto focusing is retained.
John D

PS Look at the Sigma Web Site where you will find a list of lenses and TC compatibilities.

[BruceP]

It is possible to tape over 3 of the TC pins so that the camera doesn't know that the TC is attached and this retains auto focusing above f5.6. The downside is that your lens will hunt badley for a focus lock and manual focus may in fact be quicker. Some people have even said that this hunting has caused their focusing motor to burn out.

I do use this trick on the sigma 500mm f4.5 with a 1.4TC as it only pushes it to f6.3, but even then I often switch to manual focusing.

A google search for "taped pins teleconverter" will throw up lots of hits, some of which are previous threads on this forum.

[cyber_spud]

Thanks for all the help folks. I think my best plan would be to save up for a better telephoto lens, the new Sigma 150-500 looks good or maybe the Tamron 200-500.