Nikon Nikkor 180mm f/2.8 ED AI-s. get it used here

Introduction

This is a superb manual focus lens. It is also has much rightly deserved folklore behind it as being very, very sharp. You can read more here about its development.

When it was introduced in the eaely 1980s it superseded the non-ED AI version. By reducing the secondary chromatic aberration it became much sharper then the other 180, and offered what at the time was previously unseen performance in a very fast tele.

It is not an internal focussing (IF) lens. It focusses conventionally by moving the entire lens assembly in and out as you turn the focus ring.

Specifications

It has five elements in five groups, one big one of ED glass.

It has a nine-bladed diaphragm stopping down to f/32 (the AF version only goes to f/22).

It has a built-in telescoping hood and takes 72mm filters.

It is 3.1" (78mm) around and 5.4" (138mm) long. It weighs 28 oz (800g).

Close focus is 6 feet (1.8m).

Performance

It's sharp at f/2.8 and every other aperture. As all Nikkors, it has some light falloff wide open that mostly is gone at f/4 and is completely gone at f/5.6, on FX and film cameras.

It has no distortion.

Recommendations

Again, there is very little to say about a great lens. It, along with the 105/2.5, has been replaced in most pro's bags by an 80-200 f/2.8 zoom for the sake of convenience. In the old days (1980s) you'd find one in every news photographer's bag.

They are still not that cheap to buy second hand and they are heavy. You can still get them new for $750.

You may want to consider the lighter and less expensive AF version which, being IF, focusses much faster. The AF version is a completely different lens.

And of course, since it seems that the 180mm is still no bargain, you may just as well go for an 80-200/2.8 zoom. The zoom can be as sharp, but will have more distortion, more falloff, maybe more ghosts and possibly less light transmission.