105

AIS Nikkor 105 mm f/2.5

Lens construction:	5 elements in 4 groups
Focus distance:	1 m to infinity
Angle of View:	23° 20'
Max. reproduction ratio:	1:7.69
Aperture scale:	f/2.5 to f/22
Attachment size:	52 mm
Diaphgram blades:	7
Lens hood:	built-in
Dimensions:	64 mm (dia.) x 77.5 mm (length)
Weight:	435 g

In 1959 the Nikkor 10.5 cm f/2.5 was introduced. This lens had the same optical formula as the 105 mm f/2.5 presented in 1953 for the rangefinder cameras. In december 1970 the 4 groups design replaced the original optical formula (5 elements in 3 groups) of the earlier version. The minimum focusing distance was reduced to 1 m. The AI and AIS versions were presented in 1977 and 1981, respectively.

The 105/2.5 is solidly built as most of the MF Nikkor lenses and can be rated as a top-class lens in terms of contrast and freedom of both vignetting and distorsion. It also ensures good "bokeh" and pleasant out-of-focus rendition. At infinity this lens is very sharp center to corner at f/4 onwards. The sharpness declines at wider apertures (f/2.5-f/4) near minimun focus. This fact is probably attributable to the lack of a floating elements' design. As a matter of fact, at about 1-1.5 m and at wide stops, the 105/2.5 is bettered by the AI Micro-Nikkor 105/2.8.

The images below were taken in my city with the 105 coupled to my FM (film: Provia 100).

Welcome to Rome (picture taken @ f/2.5)

Palatino (picture taken @ f/4)

Jazz players along "Via dei Fori Imperiali" (picture taken @ f/4)

"Via dei Fori Imperiali"