Hi Cindy, The first shot (even this winter sunlight) of the chrome steering wheel is blown because of the low DR of the G1. Another camera should have been able handle that, I would think. The 50/2 has good contrast and would need a bit subdued lighting (with lesser contrast as in in your 2nd and 3rd shots) for the G1 to catch all the details that lens can deliver.
The 0.7x wide converter is something I had for my Nikon kitzoom (18-55 AFS II, specifically for IR), called "Digital King". It is already in 52mm screw thread. It is a single (glass) element wide converter with the front about 82mm diameter. It works on the G1's kit zoom as well. Only problem with that converter is that while widening the field of view, also lengthens the infinity focus. As a result, the close focus distances of the kit zoom becomes longer (~0.5m instead of 0.3m at 14mm and even longer at longer focal lengths). If you want fairly inexpensive (it isn't cheap though, cost me 50 Euros, almost the same cost as the Nikon kit zoom!) ultrawide with all the auto things that the kitzoom offers, this could be it. The expected distortions are all there though.