As Preston will tell you, it's all because of the tsunami in Japan and the floods in Thailand
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Jim
No, what I would say is that these are lenses that require a huge amount of highly skilled labor to manufacture. And it takes big bucks to ramp up a manufacturing process for them as well as do the original research and design. Bottom line, I think these are really hard to make to a high standard.
Take a few minutes to watch the video of how they make these things, it is a crazy amount of manual labor. Assembly is by hand, and I'll guess that quality requirements kick out a good percentage of units after testing.
Here is the video:
http://www.youtube.com/watch?v=ovxtgj4SsiI I think this is the older, easier to make model.