Ya know, getting specific manufacturer product info from a user forum is probably not the best practice. This is a good place to get opinions and feedback from camera owners, but not specs and hard info.
You can browse over to the sony website and/or bhphotovideo.com. B&H is excellent about responding to customer questions like these.
With that said, you are forewarned to take this with a grain (or bucket) of salt..
At this time, only Canon XL models (as far as I am aware) offer changable lenses. I may have led a sheltered life, but I'm not aware of any cameras that have bayonet mounts for attachment lenses, only for interchangeable lenses.
Therefore, yeah, you'll need 58mm filters and/or attachment lenses. But wait! Before you run out and buy a wide-angle lens, why not get the camera first so you can determine just which aspect ratio you'll want?