Differential product pricing geographically has precious little to to with bi-lateral exchange rates - just look at the Economist Big Mac Index - all prices converted to US Dollars:http://www.economist.com/blogs/graphicdetail/2012/01/daily-chart-3
These consumer prices are for an identical (homogeneous) product, sure local sales taxes account for some of the price differences, but not more than 15% to 20%. The rest is predatory pricing. All multinationals do it from GM, Ford, Toyota to Glaxo-Smithkline, Pfizer and so on.
You can charge a lot more for a Big Mac in the land of Cuckoo Clocks & Chocolate than you can in a country where couples have 11, 12 or 13 children to ensure a roof over their head and something to eat in their old age.
Here's an example of a huge rip-off: in 2005 I was in Fort Myers, FL and test drove a 2nd gen Toyota Prius with a buddy of mine who'd just bought a home in Cape Coral (so he needed a car). The car dealer wanted $16,000 for the Prius, but said to my friend that if he paid cash the same day; he could have it for $14,500 - for a new car. About 2 weeks later, back in Ireland, a family friend visited driving guess what? a brand new Toyota Prius, having paid €36,000 for it (and that was including the lower vehicle tax cos' it was a Hybrid). At the time that was about US$50,000. If you accept the exchange rate argument then it would have cost just €10,000!
How do you get a 300% price differential in a product that is sold all over the world? Because manufacturers will say, well how much does X cost or what is the price of Y, then they adjust their pricing policy accordingly. It is the way of the world unfortunately.
The only way to stop Canon or others doing this, is to stop buying in one country and travel to (or buy online) cheaper countries and purchase there.