Pros: Razor-sharpness, legendary lens.
Cons: Some may desire a faster lens, or need something that is AF.
There are legendary lenses, and there are LEGENDARY lenses. This is one of them, the Nikkor 105mm f/2.5, a prime lens, always in its "prime". This lens has undergone several updates over the years, each update introducing tiny features to enhance its already great lineage. This is a great lens for both portraiture work, and to help you shoot more candidly from a distance while preserving speed.
This lens was introduced in 1959 and was a copy of the lens used for the Nikon rangefinder "S", which used Sonnar-designed optics. The original Sonnar design specified 5 elements (glass pieces) in 3 groups. The minimum focus was 1.2 meters. For identification purposes, Nikkor 105mm f/2.5 lenses which uses Sonnar optics can be identified by the "P" designation in the front of the barrel, i.e., "Auto Nikkor-P". The "P" actually stands for "penta" or 5 lens elements. Later on in 1973, a newer Gauss-type design "P-C" was introduced. The design specified 5 elements in 4 groups. This updated design made the 105 more compact, and allowed a shorter minimum focus length of 1.0 meters giving it extra shooting flexibility. The optics were also coated from this point on.
The early versions can be distinguished from their modern counterparts by the barrel design. The early versions, produced from 1959 to 1975, have vintage looking silver and/or black barrels, and a knobby focusing ring. In 1974 a more modern design was produced. The barrel was made compact, the focusing grip made into 3 rows of hard-rubber ridges, and the optics multi-coated ? the lens coating had a greenish tint. From 1977 onwards, AI features were incorporated. In 1981, starting with serial number 890001, a newer version of this now famous lens was introduced. It featured a built-in lens hood, the focusing grip had 4 rows of hard-rubber ridges, and the lens coating was now pinkish.
One of the problems with this lens is that it flares easily when pointed toward a strong light source. Fortunately, newer versions of the 105 come with a lens hood integrated into the design. The hood simply tucks back into the barrel when not in use. Using a lens hood is recommended, strong light or not, for most shooting work because it can increase the overall contrast of the image. As an aside, earlier ?vintage? versions of the 105 happened to produce softer, and less contrasty images than their modern day counterparts, making them ideal for portraiture work. Also, a vintage-style lens looks great on a modern day camera (for those who have this concern).
The lens takes 52mm filters. Like the F-mount design for lenses, Nikon also tried standardizing the filter sizes for its lenses. To a certain extent, they were successful. Many Nikkors, and Nikon series E lenses use 52mm size filters. Only until recently has a larger filter size (77mm) been informally adopted mainly because of the bigger sizes of new Nikkors, and AFs being produced.
For anyone wishing to add a lens to his or her collection/repertoire, this one is a good candidate. The Nikkor 105mm has an minimum aperture of 2.5, which is small enough to induce moderate blur of the background when you are shooting portraits, or want to isolate something in the background.
One can find a used version from such places as eBay. I guess people want to sell this lens because they want to upgrade to AF, or need a faster version of a 105mm, e.g., 105mm f/1.8 (which costs twice as much).