Panasonic's original MFT f/2.8 standard zoom — 24-70mm equiv with Power OIS before the Mark II.
The Panasonic Lumix G X Vario 12-35mm f/2.8 ASPH. Power O.I.S. launched in 2012 as the original constant f/2.8 professional standard zoom for MFT. The X designation indicates premium optics. It preceded the Mark II which added Dual I.S. 2 and splash resistance.
Optically excellent — X-series quality with constant f/2.8 across the 24-70mm equiv range. Power O.I.S. stabilisation. Fast, quiet AF. Sharp across the frame. The Mark I established MFT's professional standard zoom capability.
Micro Four Thirds mount with 58mm filter thread. Approximately 305g — compact for f/2.8 zoom. No weather sealing on Mark I — the II added splash/dust resistance. Minimum focus distance 25cm.
Available used at budget to mid-range prices — cheaper than the Mark II. The Mark II added Dual I.S. 2 and splash resistance. If you don't need those features, the Mark I is a bargain. Check for smooth zoom action.