The first is from the PanaLeica and three things are apparent even at a small size, it's sharper, more detailed and better contrast. (These are OOC JPEG's with the same settings). These were manually focused and the focus point was the same in each one, a knot in the wood.
One could argue that the Zeiss should be stopped down as much as the Leica, but it won't change the results. The Zeiss get's better up to F5.6 but it's still not as good as the Leica at F2.8. One could also argue that since both these lens were made in Japan, they are not true Zeiss nor Leica, yet both companies allowed their names to be used singly and prominently branded Zeiss and Leica by Contax and Panasonic.
My explanation is two fold, but I will likely never test it out. First off, the Zeiss is made to cover twice as large an area, it could be used on a full frame camera so using it on the PM2 was never in it's design parameters, secondly the Leica is newer technology made for the camera it was used with. So I believe that it's off to eBay for the Zeiss. As much as the name and build lends some prestige the results surely do not.
If I am right in my explanations of the differences, we have an example of how engineering in the past cannot anticipate the needs of the future. But this is just one sample and it's possible that either this Zeiss lens or this Olympus camera are just not compatible with each other....I have another Zeiss Contax, the 50MM F1.7 and I can put that to the test, what I don't have is a comparable lens for the Olympus, just standard 40-150mm zoom... More later