请问有人用过Sigma 500mm F4.5吗？

尼康的500mmF4比死马的500mm F4.5要贵一倍，还没货。听说此头的锐度还不错，是不是可以用它来打鸟？不太放心的是加死马的1.4 Teleconverter时，自动对焦不干活。想听听大家的意见。谢谢了。

所有跟帖： 

• 据说死马的标称焦距经常缺斤短两,老石要多做做homework -minime- ♂ (0 bytes) () 09/29/2009 postreply 18:18:52

• 多谢多谢！看样子，便宜没好货，好货不便宜，呵呵。 -石头城- ♂ (36 bytes) () 09/29/2009 postreply 18:22:53

• It is f/4.5 w/o OS -pieq314- ♀ (344 bytes) () 09/29/2009 postreply 19:04:35

• Right。 Non OS is the deal breaker. -minime- ♂ (0 bytes) () 09/29/2009 postreply 19:09:03

• Good point! OS 很重要吗？这样的镜头都得上架吧？ -石头城- ♂ (22 bytes) () 09/29/2009 postreply 19:14:32

• Yeah, OS is important for telephotos. -pieq314- ♀ (208 bytes) () 09/29/2009 postreply 19:26:42

• 120-300‘s focal length is acutually 280 @tele end. -minime- ♂ (121 bytes) () 09/29/2009 postreply 19:30:12

• I thought it is 300mm but the f # is slightly more than 2.8 alth -pieq314- ♀ (59 bytes) () 09/29/2009 postreply 19:33:02

• 等Sigma OS Version吧，呵呵。 -石头城- ♂ (0 bytes) () 09/29/2009 postreply 19:37:56

• try Bower 500mm f/6.3 to see if u like it or not -chicago80- ♂ (167 bytes) () 09/29/2009 postreply 19:25:37

• Well, what about Sigma 150-500mm OS instead? -pieq314- ♀ (295 bytes) () 09/29/2009 postreply 19:31:12

• 要是没买Nikkor 80-400的话，我就去买它了。现在想买个长点的， -石头城- ♂ (23 bytes) () 09/29/2009 postreply 19:41:53

• 我有Nikon的80-400，这个就不用了。谢谢。 -石头城- ♂ (0 bytes) () 09/29/2009 postreply 19:37:04