I tried to find a lighter 100mm but I think this is the lightest with its 215g. The 105mm 2,5 may be mechanically superior but it weighs much more and my initial test did not show it that much better if at all.This is a great little lens. It's sharp, fast, and tiny. You can buy one used for about $100 and its optical and mechanical performance is superior in several ways to the fantastic $1,800 80-200 f/2.8 AF-S. ...It has 4 elements in 4 groups.
It focusses to 1m or 3.5.' It takes the Nikon HR-5 screw-in rubber hood and weighs only 7.6 oz. (215g). It measures 63.0mm (2.5") around by 58mm (2.3") long and takes 52mm filters. It is single-coated, which is all it's simple design needs to give better flare and ghosting performance than the 80-200 AF-S.
It stops down to f/22 with its seven-bladed diaphragm.
For those of us who actually shoot with an open eye, the 100mm Series E is a great lens. It's far better then the disrespect the geeky collectors give it. They don't shoot..
Unlike the zooms, the 100mm Series E has no linear distortion.
It has very good ghost and flare performance, also better than the 80-200/2.8 AF-S
The main performance limitation is secondary chromatic aberration, which is minor.
Here's how it performs with aperture:
f/2.8: sharp all over, some light falloff
f/4: sharp all over, negligible light falloff
f/5.6: no light fall off and as sharp as it gets. Stop down further only for depth of field; for aerial photography this is your optimum aperture.