there are two mono filters you can use built-in. High Contrast Mono and Rich Tone Mono. High Contrast pushes the whites and blacks and will result in blown out areas of pure white and pure blacks buried in shadow. That is what it is supposed to do. Rich Tone mono does the opposite....bringing down white and blacks and keeping more steps in tonal mid-range.
Of course, if neither of those is too your liking, you can do it all in post production and have more control over the final output. I would assume that the algorithm Sony uses for its' filters is the same from camera to camera, but they may tinker with it from time to time.
It's also possible that your shot was just over-exposed. Feel free to post an example here if you think your camera is malfunctioning and our local experts can weigh in with their opinions.