The manual focus button works in conjunction with the ring on the lens; when not used for focus, the ring zooms. The function button brings up white balance, iris, and shutter speed options on the touch-screen LCD.
Though the hard disk makes the HS300 a little wider than the TM300, the placement of the accessory shoe means Panasonic had to relegate the zoom switch to the side; it's skinny and wobbly compared with the large comfortable switch on the TM300.
Despite the relatively large size of the camcorder, the mode dial is kind of small. The rest of the controls, pulled up by the bezel-based Quick Menu and Menu buttons, operate via the touch screen. Unfortunately, I found the touch screen relatively nonresponsive.