Why does the Canon 1D Mark III cost more than the 1D Mark IV?

Question

Why does the Canon 1D Mark III cost more than the 1D Mark IV ? According to snapsort it looks like the Mark IV is better.

Mark 3: $7995 http://www.amazon.com/Canon-1D-Mark-III-Digital/dp/B000NP1C5O/

Mark 4: $5399 http://www.amazon.com/Canon-EOS-1D-Mark-IV/dp/B002TG3ZYQ/

And also on Canon's website:

Answer

The EOS 1Ds Mark III is Canon's top-of-the-line full-frame DSLR: 21MP; 45 AF points; dual DIGIC III processors.

The EOS 1D Mark IV (that's 1D, not 1Ds) uses a 28.1 × 18.7mm sensor which is smaller than a 36 x 24mm full-frame, but bigger than the 22.3 × 14.9 mm sensor in the Rebel, 60D, 7D, etc.

The main tradeoff with the 1D Mark IV vs. the 1Ds is that you get a slightly lower image quality but continuous 10 fps shooting vs. only 5 fps on the 1Ds.

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