Yes, you have a modern front derailleur of the type Hillrider warned against above. The dropped inner cage plate interferes with shifting when the tooth difference between rings is too small. What you need is a vintage front derailleur designed to work with half-step gearing, e.g.:



N.B. Campagnolo isn't the only one available, althpough it is among the best quality. Similar units were made by Huret, Simplex, SunTour, Shimano, and others. The important feature you're looking for is the shallow inner plate as seen in the picture above. This allows you to lower the derailleur enough to place the outer plate just a couple millimeters above the outer ring's teeth, for best shifting performance.