Quote:
In the UK the EF 70-300mm f/4.5-5.6 DO IS USM cost £849 and it weighs 720g.

The EF 70-200mm f2.8 L IS USM and EF 1.4x II Converter combined cost £1,608 and weigh 1790g.

Wow, that's a good deal more money than we pay in the U.S. At that point, it's cheaper for you to book a flight to New York, buy your gear (even paying sales tax), and fly back home again.

In terms of mass, there's definitely a big difference between 720g and 1790g. Interestingly, your Canon 75-300 (with IS and USM, but without the fancy DO optics), weighs only 666g. The Nikon lens (similar optics, but no IS or USM) is 517g. I suppose it makes sense that adding the ultrasonic motors and image stability systems could cost 140g. I'm actually somewhat surprised that the DO version is heavier. I would have thought that with more expensive optics, they could get that weight down. Maybe they're putting in heavier AF motors or a more robust outer shell.