Once upon a time, professional photographic equipment held its value well for many years. That was then and this is now. 
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In order to buy a Canon EOS 1D Mark II camera body one year ago you had to put your name on a waiting list. Demand vastly outstripped supply even though the camera was released three months earlier in April 2004. The price was $4,500 US no matter where you looked.
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Today you can purchase a new Canon EOS 1D Mark II for about $3,500. A used one might fetch something like $3,000, depending on condition. That is a 33% loss of value in just one year. Canon EOS 1Ds camera bodies have been around longer and were replaced by the Mark II version about eight months ago. They originally sold for $8000 and now go for about $3700, less than 50% of the original value. Not many things depreciate at such high rates, except computers.
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Welcome to digital imaging.
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