All raw files were reset to a standard daylight white balance of 5500K and no tint in either green or magenta. The cameras were all shooting at ISO 320, f/2.8 at 1/125th shutter speed.
The biggest difference was actually between the two Leica sensors from the M 240 and the M9 as you'll see.
As you can see, there is very little difference between the two lenses. I found that the bokeh is slightly circularly distorted around the edges on the Zeiss Biogon lens, but it is hardly noticeable. The Leica Summarit lens had a very slight magenta tint, but nothing to worry about and easily adjusted.
As you can see, the biggest difference is between the M 240 and M9 sensors. The M9 CCD has quite a noticeable green shift from the M 240 file. While lenses can have subtle colour and contrast differences, you'll often see the bigger differences between camera models, just like you would with choosing difference film stocks.
review images by Nick Bedford