I've only one Contax, and it's a 167MT - bought so that I could get my hands on a "Zeiss" lens. Unfortunately, although it most often gets the correct exposure, it frequently over-exposes quite seriously - in a way which suggests malfunction rather than a metering fault. (Several times per film.) I haven't yet worked out whether it's a lens problem, sticky shutter or other cause - so I'm a bit biased against it.