One of the Konica's Hexar lenses. Similar to the Series E line for Nikon and Celtic line for Minolta these are "economy" versions of the main line Hexanon lenses. However 70's economy is very different than modern economy. This is a tank of a lens with stunning build quality. It is surprisingly large as well for its slow aperture. I do think they were conservative though as realistically it's more like an f/3.2 lens. This is interesting as most makers are optimistic in their calculations with f/2.8 lenses often transmitting an effective f/3.5. I picked up mine on eBay for a great price. They're quite common and because of the Hexar name they're not terribly in demand which keeps prices low.
Mount: AR Mount
Focal Length: 135mm
Aperture Range: f/3.5 - f/16
Minimum Focus: 1.5m
Filter Thread: 55mm
Data Source: All Photo Lenses - Lens-DB
Date Acquired: 06/01/2019
Serial Number: 4222598
Purchase Price: $15
Going Price: ~$25
The build quality is exceptional. For being an "economy" lens I really struggle to understand what is economy about this lens. I suppose there are some interesting corners they cut but overall if you told me this lens was made by Leica I'd probably believe you. The focus is smooth and the integrated lens hood is handy. The only real problems I had are with the size and the aperture ring. The lens is shockingly large for having such a slow aperture. For comparison the Canon nFD 135mm f/3.5 and Olympus OM 135mm f/3.5 are both about 200g lighter and substantially smaller. It really calls into question just why did the lens have to be this big? The aperture like most Konica AR lenses is stiff and has very few steps. In fact the bokeh test below at f/16 is stopped all the way down where most other lenses can go to f/22.
Performance is simply amazing. I want to remind you I spent $15 on this lens. It is tack sharp across the entire frame wide open. Vignetting is negligible and flare is generally well controlled. Bokeh is extremely smooth and and doesn't render distinct polygons when stopping down. This level of performance meets or exceeds modern lenses at a fraction of the price.
The lens in use is fantastic. Focusing is easy and the images are great. It is a little large for a 135mm f/3.5 lens but not unmanageable. Overall it's a great lens especially if you already make use of Konica AR lenses.
Should I get one for photography?
Definitely! You can get the performance of lenses that cost over $1000 for less than a meal at a fast food restaurant. Just get one - you really don't have a reason not to.
Should I get one for a collection?
Eh.... that's a harder question to answer. The Hexar's aren't seen as collectors items and I can see why. This is a very functional lens. The design makes it clear that this is strictly a photographic tool. Combined with the general community neglect of Hexars and it's rough to recommend for collecting purposes except for the fact that it's so cheap. Even if it's not a great fit for a collection the low price makes it a much easier pill to swallow.