A big lens that renders amazing portraits in a very attractive package. The scale of this lens rivals modern Sigma Art glass in terms of scale. The photos this lens takes though are as beautiful as the lens itself. The truth is that vintage telephoto lenses are almost as sharp as modern lenses just with inferior coatings and no auto-focus. The lens is on the rare side so you should seek it out for collection purposes. If all you're interested in is performance the Takumars are a better option. I got incredibly lucky and managed to get mine on eBay for just $24 - a fraction of what it was worth.
Mount: M42 Screw Mount
Focal Length: 135mm
Aperture Range: f/2.8 - f/22
Minimum Focus: 1.5m
Filter Thread: 55mm
Data Source: All Photo Lenses - Pentax Forums - Lens-DB
Date Acquired: 05/16/2019
Serial Number: 3101249
Purchase Price: $24
Going Price: ~$120
Condition: Some light scratches and internal damage to coatings but does not impact IQ
Like all Yashinon-DX lenses the build quality is similar to that of a Swiss watch - absolutely stunning. The lens is absolutely beautiful with a very well damped and smooth focus ring, a deep integrated lens hood, and an automatic/manual aperture switch. The aperture ring like all lenses of the line is the only part that is a bit of a let down as the small cutout window makes it hard to see what aperture you're currently using. The black enamel seems more fragile than the chrome plating as well if my copy is anything to go by.
Given the age of the lens the performance is remarkable. The center is tack sharp wide open with the corners only slightly softer. They improve slightly at f/4 but become sharp by f/5.6. Vignetting isn't bad and disappears after just one stop. The simpler single coatings used unfortunately don't do a great job handling flare with distinct internal reflections visible. Bokeh is very smooth no matter the aperture. Overall a great showing for a lens over 50 years old.
In the hand the lens is an absolute joy to use like all the other Yashinon-DX lenses. It fits naturally in your hand and largely disappears except for when you want to change your aperture. That annoying little cutout window demands you move your eye from the viewfinder and look at a very specific part of the lens which is frustrating. Still in most situations you're not going to change aperture that often (at least the way I like to shoot) so this is largely a non-issue.
Should I get one for photography?
My comments about the Yashinon-DX 50mm f/1.4 apply here as well. Unfortunately the rarity of the Yashinon-DX line results in them commanding higher prices than equivalent Takumars makes it hard to recommend them. If you can find one for a good price then go for it but odds are the equivalent Takumar is cheaper and a match in performance.
Should I get one for a collection?
This is definitely a fine lens to add to a collection. The distinct appearance of the Yashinon-DX line combined with the good performance and age of the lens make it a no brainer. The price can run high so be mindful to get one at a good price but otherwise it's a good addition for any collector.