这次用尺格子测试: XXB 还是不行.
on tripod, 10D, remote release, no sharpening.

XXB 200mm f4 center resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/xxb-200mm-f4-center-resize.jpg[/IMG]

Sigma 200mm f5.6 center resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/sigma-200mm-f5.6-center-resize.jpg[/IMG]

Sigma 300mm f5.6 resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/sigma-300mm-f5.6-resize.jpg[/IMG]

xxb 200mm f8 center resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/xxb-200mm-f8-center-resize.jpg[/IMG]


sigma 200mm f8 center resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/sigma-200mm-f8-center-resize.jpg[/IMG]


sigma 300mm f8 resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/sigma-300mm-f8-resize.jpg[/IMG]

xxb 200mm f16 center resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/xxb-200mm-f16-center-resize.jpg[/IMG]


sigma 200mm f16 center resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/sigma-200mm-f16-center-resize.jpg[/IMG]


sigma 300mm f16 resize
[IMG]http://www.scripps.edu/~hxiong/lenses-comparison/xxb-sigma2/sigma-300mm-f16-resize.jpg[/IMG]

Conclusion:
This copy of XXB on my 10D back focuses @ 200mm
The sigma 70-300mm is acceptable @ both 200mm and 300mm.

[此贴子已经被作者于2004-8-25 3:26:57编辑过]

这个测试说明XXB在10D上还是对焦很准的, 至于锐度也没有什么太大的区别.
出去外拍几张, XXB的色彩还原很好的, 不是Sigma能比的.

很专业。