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08-06-2012, 09:23 AM   #31

Join Date: Oct 2011
Location: Savannah, GA
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QuoteOriginally posted by bxf Quote
Now, I was curious to see how the "small" and "large" images compared when re-sized to the same magnification, and I got quite a surprise: the 300mm shots actually appear noticeably sharper than the 150mm shots of the same subject. This appears to be the case regardless of which direction the re-sizing is performed.
Well of course they do as the bigger ones had a higher resolution to begin with. If they were the same we wouldn't need long lenses at all. A better test is to frame a flat subject the same way at both 150mm and 300mm -- in other words stand closer at 150mm to get the same framing. Now each image starts at the same pixel resolution and you can compare apples to apples -- the 150mm will likely be sharper. (Use the same aperture.)

08-06-2012, 02:59 PM   #32
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Join Date: Jul 2010
Location: Lisbon area
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Nothing like being confronted with the obvious to make one feel like a fool, so thanks for that Still, I'll do as you suggest, just to satisfy my curiosity.

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