回复：在Ebay上面下单买了镜头，有几点疑问望各位指教

我目前的问题有以下几个：
（1）Tamron镜头描述中的“LD”是什么意思？在fredmiranda上查到“XR”这个专业词汇的意思是“Extra Refractive Index”，这是否是和“LD”是相对的东西，是否就说明我买的那个镜头上面没有所谓的“XR”功能？

You do not need to worry about these technique details. If you really want to know, I think "LD" means low dispersion. These are not standard terminologies. They are invented by Tamron. So check Tamron.com for exactly what they mean.

All you really need to care about is that the lens has Canon EF or EF-s mount.

（2）“IF”是什么意思？Canon镜头上面的“IS”是“Image Stable”功能的意思，这个“IF”呢？

"IF" means internal focussing. Again, do not worry about what it is.

（3）Ebay上面的seller Deion说卖给我的这款镜头是专门供Canon EOS EF Mount，其中也包括了我的Rebel XT（350D）。但是我在Australia的Ebay上面查到有一款Nikon D70相机的Deal，随机附带的镜头就是我这个“Tamron 171D”，难道我买的这个镜头是兼容Nikon而不是Canon的？

Tamron can put different mounts on this lens (that is, same optics but the connector to the camera is different).

（4）我在Dealsea等网站上面找了很久，也没有找到我这款171D的镜头，那上面“Tamron Zoom Wide Angle-Telephoto AF 28-200mm Super Zoom f/3.8-5.6 Aspherical XR IF Macro Autofocus Lens”的Nikon版和Canon版的价钱分别是$149和$285，相差了差不多一倍，但这些镜头我都找不到他们的Model ＃，所以我现在也搞不清楚我买的镜头到底是属于哪个款的，是亏了还是赚了。

This lens costs about $300. So the Nikon version for $285 is the normal price. If yours is new for $149, it is a VERY good price. Again, do not worry about Model # (It could be an older version. Lens makers constantly update their designs, and in general, news models are better by just a little bit). If you suspect yours is not good, just go take some pictures to see if the pitures come out good or not.

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• 回复：回复：在Ebay上面下单买了镜头，有几点疑问望各位指教 -天涯倦客- ♂ (41 bytes) () 12/07/2006 postreply 10:45:54

• Yes, they are very nice and knowledgable. -sqllsq- ♂ (0 bytes) () 12/07/2006 postreply 16:37:56