You can’t find any data about this. Sony does not mention this in the manuals or on the web. The A57 shoots some horrible video, even with the kit lens. You can hear the lens moving on the video! With Sony lens and with other lens.

There are two solutions to avoid this: use an external microphone or a SSM lens. A mic goes for about 100$ on amazon, but the lens are more expensive. For example, my Tamron f/2.8 costs 500$, as a similar lens from Sony costs 1.000$.

Here is the kicker: who will buy a 1.000$ lens for their 500$ DSLR? Exactly, very few people.