There is no 'contrast' balance as such, but you can adjust the black/white balance in so many other ways. Once your white balance has been set, you can either play with the custom presets, or the iris ring to control the exposure. You can also manipulate the white levels by setting your white balance to a warmer or colder white color.
Having said that, correcting the contrast in post is the most accurate way of adjusting the contrast. I always shoot with either a preset or shoot it raw and do all the color correction in post.
