[Guest]

Pro lenses aren't often heavy because of the optical components but because of the construction.

I'm sure you could put the 28-300L into a plastic housing with a total weight of less than half of the current lens.

The 12-100mm could certainly be shaved by at least 150g using consumer-grade housing.

The nice thing is that mFT now finally has some choices for the traveler ranging from expensive "pro" zooms like this one and the announced panaleica's (e.g., 12-60 F2.8-4) and the cheaper and much lighter consumer zooms from Pana and Oly. The format is starting to become really attarctive, to me at least.