This is a surprisingly fast and quality portrait telephoto that will probably outlast us all. When all that's left are cockroaches and nuclear fall out you'll probably find mint copies of the Takumar 135mm f/2.5 around. The lens is pretty big and hefty made completely out of metal. It has a big for its time 58mm filter thread and a huge metal screw in hood to match. All this weight protects a fantastically sharp optic that rivals modern lenses in rendering quality. They definitely don't make them like this anymore. I was given my copy with the CEO of the company I was working for at the time left and couldn't be happier. If you're looking for a telephoto portrait lens in M42 mount this is a good one to consider.
Mount: M42 Screw Mount
Focal Length: 135mm
Aperture Range: f/2.5 - f/22
Minimum Focus: 1.5m
Filter Thread: 58mm
Date Acquired: Approximately 2013
Serial Number: 2508733
Purchase Price: Free
Going Price: ~$100
Condition: Auto/manual ring fell off and there's some edge wear but optically perfect
There's nothing surprising here. Like all Takumar lenses this one is a veritable tank of a lens. All metal with a massive focus ring. The aperture is easy to control and has an auto/manual switch making adapting very easy. The filter thread is unexpectedly large for a vintage prime at 58mm but that's not problematic. Unfortunately there is no integrated lens hood like most contemporaries but it did have a very nice matching metal screw in lens hood. If you're shopping for one of these try to find one that comes with the hood.
Performance is generally really good. The lens is a little soft wide open in the center and fairly soft in the corners. Stopping down to f/4 makes the center tack sharp and eliminates vignetting. Unfortunately the corners never really improve. The lens is remarkably resistant to flare for such an old design. Bokeh is very smooth at all apertures with no real issues.
I'm personally not a huge fan of the ergonomics of Takumar lenses but they are very functional. The huge focus ring falls in the hand nicely and everything just works well. If you like the other Takumar lenses you'll find using this one very natural.
Should I get one for photography?
Maybe - it's not a bad lens and can be found for a decent price but honestly speaking the Konica Hexar 135mm f/3.5 existing makes it hard to recommend. The Konica is much sharper and much cheaper means that unless you have specific reasons to get the Takumar you should really look at the Konica instead. If you really want an m42 or a Takumar specifically though then it might be worth considering.
Should I get one for a collection?
If you're already collecting the Takumar line then it goes without saying you should add one to your collection. The Takumars in particular have a very distinct look and amazingly high build quality making them a natural inclusion in any collection.