Tamron 135mm f/2.5 (03B)
This is another Tamron lens I've been meaning to add to my collection for quite some time: The Tamron 135mm f/2.5 (model number: 03B). Like most Tamron fixed-focal length lenses this one has a faster than usual maximum aperture of f/2.5. Anyone used to modern 135mm lenses, many of which these days have a maximum aperture of f/1.8, this will seem hardly worth mentioning. But back in 1979 when this lens was introduced as one of the first Tamron Adaptall 2 lenses, it was a good way for Tamron to differentiate this lens from typical OEM 135mm lenses with a maximum aperture of f/3.5 or f/2.8.
The build quality of this is very nice indeed. Like all early Tamron lenses from this era, it's made from reassuringly cool metal. Despite the generous maximum aperture, this lens is reasonably compact and light weight, weighing in at 473 grams complete with a Pentax K adapter (the lens alone weighs in at 410 grams). There is a built-in lens hood, which is a nice extra, or at least it would be if it was a decent length! But it's so shallow it isn't really worth bothering with.
The Tamron 135mm f/2.5 isn't especially sharp, but I've never considered sharpness to be a particularly useful metric by which to judge lenses, and I was very happy with the results from this lens. And that slightly faster than usual maximum aperture results in some nice, characterful bokeh when shooting wide open.
Photographs taken with the Tamron 135mm f/2.5
Links
Tamron 135mm f/2.5 (03B) on the adaptall-2.com website