Specifications
It takes 62mm filters in its plastic threaded front.
It has fifteen elements in eleven groups.
It has a seven-bladed diaphragm stopping down to f/22 to f/28, depending on focal length setting.
It focuses to 2.8 feet at all focal lengths. It gets to 10" in the manually-focused macro mode only at 28mm. This does allow some fun photos not possible otherwise.
It takes an HB-1 hood I've never used.
Its 2.8" (71mm) around by 3.5" (89mm) long and weighs 19 oz (540g).
Performance
AF speed is about average to a little slower than average. One full turn of the AF screw focuses the lens from infinity to 15.'
There is no vignetting if used with a Nikon filter. It will vignette at 28mm with a thicker filter like a Tiffen or B&W. It works OK with 67mm filters and step-up ring, and of course works great with 77mm filters and a step-up ring. At 85mm none of this is a problem.
It has the typical well-behaved distortion you expect with a zoom: barrel distortion at 28mm, neutral at 50mm, some pincushion at 70mm and stronger pincushion at 85mm. It has simple, low order distortion easy to correct with the "spherize" and "pinch" filters in Photoshop.
It is pretty sharp at all apertures and focal lengths; just about as sharp as my fixed lenses. The only gotcha is some softness in the corners at 28mm wider than f/8, but I can handle that as its only flaw. It is uncanny how bad the other zooms look compared to this one at full aperture, which is where I usually am shooting with Velvia. This is really good performance.
It has no significant light falloff wide open at any focal length, better than most fixed focal length lenses. On the other hand, it needs this because most fixed lenses are much faster, and by f/4, where you often need to shoot, the fixed lenses are already stopped down a good deal. This is the way lenses ought to be, and this is one of the few that is.
If you really ask for it you will get a green ghost or two if you put the sun in your image. It's pretty good about flare and ghosts. I never use a hood and don't need it. Then again I'm careful to use my hand if the sun is shining on the front of the lens.
For you cold weather buffs it autofocuses just fine at zero degrees Fahrenheit, but the zoom ring freezes stuck.
The macro mode requires pressing a button and moving the zoom ring past 28mm. In the macro mode you are in manual focus, regardless of what camera you have. Macro mode only works at 28mm.
