Teleconverters

I have a Pentax *ist DS and an older 2X teleconverter (Vivitar) that does auto apperture but not autofocus, do the newer teleconverters do autofocus as well?

When using the teleconverter the apperture readings are not displayed correctly because it shows readings that are lower than they should be, is this normal or is this converter stuffed?

Thanks.

Pete :confused:

by lower than they should be you mean lower than the lens is able to without it? I think its supposed to change the widest aperture you can get

Sorry by lower I mean that when the camera should be displaying say F4 with the converter on it will display F1.2.

I tested it side by side with a new Kenko converter today in the shop I got my camera from and the new converter worked just as you would expect a lens with no converter to work and the old one gave the lower readings, I took a photo with each and had a look once I got home had a closer look, both photos are fine, perfectly exposed. I think I will spend the money and get a new one though as the new ones do auto focus as well, price here in Australia is $259 Aust.

Cheers.

Pete