主题：【原创】Canon的失落（增补版） -- 晨枫
ISXB在全幅上的表现好于减幅？
5.6没戏哈，加上1.4x画质够呛，要是再加个2x上去，估计和拿200放大点儿差不多了。
我用了十多年了，爱不释手。画质没说的，构造结实，平常磕磕碰碰没事，摔一下只要不太狠，也没事。缺点是重、贵。要是经济上承受的起，肩膀或者脖子也承受的起，绝对推荐。我的是非IS的，IS的画质据说更好，但改善有限；更重，这个我一托就感觉到了；也更贵。不过非IS的现在还在卖，要是可以牺牲IS的话，个人觉得这个比差不多同价的70-200/f4L IS要更物超所值，f2.8的bokeh不是f4能比的。运动物体需要加快快门，这也不是IS能补偿的。
……However this excellent full-frame performance does come at some cost to APS-C users; perceived sharpness is reduced (due simply to the extra magnification imposed by the smaller sensor), and this amplifies the impression of softness wide open. Of course on APS-C the lens still benefits from the 'sweet spot' effects of extremely low distortion and negligible vignetting, so in the grand scheme of things this is something of a case of swings and roundabouts, with different benefits enjoyed by users of each format.
A comparison to Nikon's AF-S VR 70-200mm F2.8G is particularly interesting. The two lenses are near-identical in specification and price, but their characteristics are substantially different. The Nikon lens clearly outperforms the Canon for sharpness on the smaller DX/APS-C format, however this comes at the cost of rather compromised performance on full frame, with significantly higher distortion, vignetting and chromatic aberration, plus extremely soft corners. This leads us to conclude that the two lenses were optimized differently, the Canon for full frame and the Nikon for DX, and illustrates how the different demands of the two formats appear difficult to reconcile in a single lens design.
我看看前面和后面，好像差不多。
据说所谓的镜头数码优化指的是尾部的镀膜不太一样，因为胶片和CMOS的反光特性不同，光线会在CMOS和镜头尾部多次反光，所以造玻璃片儿的就在尾部的片子上涂了点儿东西。
咬牙进了70-200/f2.8L 非IS的,估计3个月不能吃big mac了
要有的话,整个镜头的镀膜设计都要改.数码优化,不是简单的将没镀膜的镀镀就可以了的.
这投资可不少。
这镜头就我来看，值！什么时候都不亏的。
俺怎么感觉，晨大这一通白话儿，佳能就多卖出一个玩意儿，说，老大，C给了你多少回扣来着？
我真的应该找Canon要一点commission了，最近帮Canon卖出了好多玩意儿……
应该比你的投入多个1k吧。