The main feature of this version is that aside from the record/stop, focus and power on/standby buttons also found on the 522 LANC models, it gives you three different zoom speed control buttons. The unit ships with these buttons as general use presets, but you can rapidly customize them to your own personal zoom speed levels!

The zoom speed buttons set the upper limit of the range of movement of the zoom wheel and determine whether the zoom is progressive as you exert more pressure on the wheel, or fixed no matter how far you push the wheel. Being able to set a fixed zoom speed is an obvious advantage, since you can cut out the risk of accidentally putting too much pressure on the zoom wheel and ruining the shot half way through. The progressive set speed feature is even more flexible: the zoom wheel in full min-max range has 8 different speed positions, so as you gradually turn the wheel further, it steps up gradually from a slow to a rapid zoom. By selecting the lowest zoom speed, the whole arc of movement that normally covers all speed steps only covers a few of them, meaning that you can easily keep zoom limited to a slower range that you might find more suitable for your subject.

Whether you choose a limited progressive zoom range or a single fixed speed, the features of the 523 mean you can easily repeat zooms precisely in subsequent takes of the same shot.