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Old Mar 17, 2005, 12:10 AM   #11
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rob_strain wrote:
Adorama has the Sigma for $699.

I cant say about the speed of the Canon, but the Sigma is nice and fast on my 20D.
It still looks like $799 to me. . .but I might not be seeing the same thing
They DO have refurbed 70-200 f/4Ls for $499 however:G(not that I would actually get one)
here are the MTFs @200mm
Canonvs. Sigma

You tell me which is better. . .(I don't know all the ins and outs of the MTF charts yet. . .):lol:
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Old Mar 17, 2005, 5:55 AM   #12
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KM_krazy wrote:
You tell me which is better. . .(I don't know all the ins and outs of the MTF charts yet. . .):lol:
You don't compare lenses with different aperture values (hence apples vs oranges) :idea:

Here's the correct ones:

Canon: vs Sigma:

The blue lines on Canon's are at f/8 (a lens is always sharper when closed down), hence at 70mm f/2.8, with the black lines (@ wide open), the Sigma is sharper... Sigma do not plot closed down to f/8!

Canon: vs Sigma:

The Canon is sharper at 200mm f/2.8; However the Sigma is still a better lens overall since it's flatness extend to the corners/edges of the lens (see the sharper fall off at 20 on the chart), this is only critical if you move on to a full-frame

The MTF's are only 1 aspect of comparison, there's also 'Bokeh', contrast, value and flexibilities of a lens which are not figured in the equation - Another example is with f/2.8 you can get 400mm f/5.6 with a 2x TC and still be usable -> at 400 @ f/8 with a 70-200 f/4 you will lose the AF focus...

Beside all bets are off since there's a new improved DG version for digital coming out
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Old Mar 17, 2005, 6:20 AM   #13
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They did have them for $699 a few weeks ago, I guess I should have checked again to be sure. Sorry about that.
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