WhiteBeard: About pricing... A long time ago, lenses were made with a lot of metal and glass - not polycarbonate - and 70-200mm zooms (35mm eq.) were the most popular and mostly least expensive zooms available. Now, Panasonic wants to make us believe that putting an O-ring, less glass (polished by much more precise and efficient automated means than before) and putting back some aluminum instead of the usual polycarbonate is sufficient to warrant a 1500$ price tag... Anybody out there familiar about Marketing Theory and the expression "Whatever the Market can bear"?
To WhiteBeard:I agree with what you've stated: "Whatever the Market can bear". Today, most people don't realize the consumer and so-called prosumer lenses are crappy in terms of build quality compared to lenses made back in the 1970s. I remember fondly the Vivitar Series 1 zooms, e.g., 35-85 f/2.8 and 70-210 f/3.5 zooms. These were solidly built precision quality craftsmanship with constant aperture throughout the zoom range and semi-macro (1:4 and 1:2.2 respectively) focus. And they gave the Canon/Nikon/Olympus zoom lenses a run for their money.
On the other hand, even back in the 1970s, a zoom with a constant f/2.8 aperture commanded a premium price compared to zoom lens with a somehwat slower f/3.5 or f/4 aperture that were the norm back then. But even those "common" zooms had constant apertures throughout the zoom range.