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Old May 20, 2009, 2:06 PM   #21
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I posted two samples. First one was at 100mm. Second one was at 200mm
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Old May 20, 2009, 2:23 PM   #22
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Sorry, I didn't even notice that you had two sets posted. lol

But, the same thing still applies. If you stop down a lens more, you tend to get better contrast and sharpness, even though the differences are not as great at 100mm with those two lenses. You also have variations between copies of lenses to contend with, and some lenses are going to be softer at some focal lengths.

To me, the lack of CA and a longer 300mm focal length with the 100-300m would be more important when comparing them if I were looking for a longer lens (especially since you'd have roughly twice as many pixels representing your subject if you needed to zoom in more to fill the frame versus cropping with the 70-200mm).

Each time you crop a photo to make it look like you used twice as much optical zoom, you end up with only 1/4 the original pixels. But, personally, most of my photos are taken at relatively short focal lengths and I really don't have a lot of use for either lens.
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Old May 20, 2009, 3:37 PM   #23
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Yes, there's less CA in the 100-300 APO than in the Beercan, which I don't find surprising.

What I do find surprising is that, at 200mm, the 100-300 APO, wide open, is as sharp as the Beercan stopped down (that is, with both of them at f/5.6.) In my experience, the Beercan sharpens up quick and then stays pretty constant until you reach the diffraction limited f-stop. Comparing it to the 100-300 wide open isn't exactly fair, but the 100-300 came out reasonably well.
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Old May 20, 2009, 3:47 PM   #24
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Beercan sharpness drops a bit at 200mm. APO picks it up. I also took pictures at F5.6 and F8. Beercan is much sharper at 100mm on all apertures (including F8).

At 200mm, the sharpness is about equal at F8. Beercan is slightly sharper on borders at F5.6
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Old May 20, 2009, 3:52 PM   #25
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I bet the APO is also sharper at 300mm.
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Old May 20, 2009, 4:19 PM   #26
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In any case, beercan has advantage that it's constant F4 which makes it better for portrait. Moreover, it's cheaper. (about $100). Tamron 200-400, though not known as that good, will make better combination with the beercan.
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