今天试用了NIKON28-105D后，感觉成像不如28-70DF3.5-4.5镜头锐利，这个头到底好不好？请各位用家评论。

一直在用28-105这支头，感觉上是不够锐利，特别是在50mm之后焦段。不能说是很好，也能接受吧！不过总体上的感觉就是表现中规中距，在色彩的还原跟广角段的变形都很好！我虽然没有28-70mm，但从人家的片子来看，是比较利的，而且色彩的浓度跟反差就很有NIKON味，至少在同焦段比28-105mm好！
不过28-105mm就价钱而言是很值的，也不算太狗吧！

To 各位
   抱歉抱歉,我说的是28-70的那只镜头.
   当年我就是凭着这只镜头的锐利特点,在另外两只用定焦尼康头的菜鸟面前"出尽了风头",真是恨不得写篇"变焦大大强于定焦"的个人体会文章.
   

TO小菜
归纳得好，同感。

确实，NIKON 28-70F3.5-4.5的锐度是非常好的！尽管有评论认为它是狗头。
我有NIKON 28-70F3.5-4.5和35-70F2.8，没有28-105。我觉得单就锐度而言，28-70F3.5-4.5比35-70F2.8还高！我大多数时间拍的是黑白片，对这一点很敏感。
然而，镜头的锐度和分辨率是两个不同的概念。我记得M.兰福德在他的《高级摄影教程》里，曾经引用蔡司公司的样片证明：高分辨率的图象比起低分辨率的图象，在视觉上显得锐度较低，反差较小(原意如此)。
我们不能仅仅以分辨率的高低或是锐度的大小来评价镜头。其实，镜头的设计者也是在分辨率和锐度之间作了一定的折衷的。而关键还是在于使用者的个人喜好。
对于你的这个问题，因为我没有28-105这支镜头，不好说孰优孰劣。但是就我个人感觉而言：在我刚迷上摄影的时候，特别喜欢那种高锐度、高反差的片片；但是最近这两年来，越来越喜欢柔和点的片子了。这一点在我的片子上可以清楚的感觉到。
(刚刚敲了半天，脚又不小心踢了一下电脑连线，居然短电了，只好重敲，气S我了！ )

您说的是28-70/3.5-4.5D 这支头吗?

   这只镜头我用了有5年,几乎各种条件下都拍过了,归纳它的特性,一是清楚,很多情况下都能拍出你周围人认可的"清晰"相片.二物体边缘感很强,感觉像个"框框".三 色彩较为中性,较为清亮.四.畸变纠正很好,几乎感觉不出变形.五 阴天拍的片子明快,晴天的片子就显得反差过高了.
   

经过实拍对比，从28MM到70MM，不同光圈条件下，大多数情况28-70要比28-105好那么一点点，比如色彩要艳（主要在兰色上比较）一点点，对比度OR锐度（比如蓝底白字）要高一点点，角上的颜色要亮一点点，当然，只有一点点。

没有用脚架，用的大概是28-50这一段较多。

您比较的是长焦端还是广角端？
国外的评侧28-105好象在28mm好些。

This lens is fairly compact (at 28mm... - it grows considerably in length when zoomed to 105mm) and takes 62mm filters. The focus is VERY short-throw (about 1" movement from infinity to 2'), reasonably well damped, and has a "geary" feel. The zoom action is moderately smooth, reasonably tight, and the lens does not "self-zoom" when pointed up or down. The filter ring does not rotate with focus, but rotates some when the lens is zoomed. The macro function locks out focal-lengths shorter than 50mm. There is very little magnification difference at minimum macro focus distance when zooming between 70 and 105mm. Front clearance at closest focus (1:2 at 105mm) is almost nonexistent, making using this lens in macro mode quite unlike using a 105mm macro lens. Macro sharpness away from the center of the frame at 105mm and 1:2 was quite poor at f8. The 1:2 macro mode feature of this lens should not be taken seriously since it is awkward to use, and poor in performance). This lens has VERY low linear distortion, being close to zero from 35-105mm, and very slight at 28mm (very slight barrel at 28mm, VERY slight pincushion at 105mm). For a wide-range zoom, especially one including the wide angle end, linear distortion is unusually low. The viewing image when used with an F3 was rather dark, and not particularly crisp-looking, which, combined with the rapid focus, makes accurate manual focusing difficult. This sample showed only very slight optical misalignment except near 105mm, where it was moderate (the right side of the frame was somewhat less sharp than the left, noticeable at 10X enlargement even at f11). Center to corner sharpness uniformity was unusually good for a non-tele-only zoom. At 5' wide-open, sharpness overall was good, with very slightly softer corners at 105mm, and somewhat softer corners at 28-35mm. At infinity wide-open, the image sharpness was good, but slightly diffuse. At marked f5.6, the image improved, lost the diffusion, and was good to the corners except at 28mm, where it was OK in the corners. This is very good performance for this kind of zoom lens. At f11, the image quality improved overall, and was quite good. I compared the 28-105mm with a good-sample 28-70mm f3.5-4.5, and found the two lenses close in performance, but with the 28-70 a bit sharper over all of the frame at f5.6 except at 28mm, where the 28-105 was better at the edges and corners. The differences narrowed at f11, where both were quite good throughout their zoom ranges. (Applied to the above comments should be the observation of the alignment problem found in this sample of the 28-105mm...) Over all, this is a good moderate wide-to-tele zoom, with amazingly low linear distortion and very uniform sharpness everywhere within the frame at normal focus distances and all FLs, from about f5.6 - not bad for a 28-105mm zoom!