Porst Porst 135mm f2.8 Heritage

Overview

The reviews provided actually document the Porst Tele Auto 135mm f/1.8 (a superfast MF portrait lens), not the f/2.8 variant requested here, so specifics for the f/2.8 are unknown. According to the Pentax Forums database entry, the branding 'Porst' was applied to a lens family made by Mitake, using a 5-element/4-group optical design that was rebranded across a bewildering range of names: Spiratone Plura-Coat, Computar, Promura, Kenlock, Formula 5, Eyemik, Apollo, Ultra-Unitor, Accura, Varo, Vivitar and Weltblick. Porst itself was a German photographic retailer that sold rebadged Japanese optics under its own name. At least four distinct optical designs existed for the 135mm f/1.8 class before Pentax released its own SMC-A 135mm f/1.8. No established nicknames or community jargon (such as 'Bokeh King' or 'Iron Curtain') are evidenced in the reviews for this lens. The lens is loved for its dreamy, painterly portrait rendering born of its huge aperture and soft optical character.

Verdict: The reviews supplied describe the Porst 135mm f/1.8 rather than this f/2.8, so specifics for the f/2.8 are unknown. If it shares the family DNA, it is a portrait-first, character-heavy lens for shooters who value a dreamy, painterly look and creamy bokeh over clinical sharpness — and who don't mind heavy, stiff-focusing all-metal handling.

Community Insights

What people love

Dreamy, painterly portrait rendering (per the f/1.8 reviews)
Exceptional, creamy bokeh that adds to the image
Superb, all-metal build quality that feels like a beast
High reviewer ratings (100% recommended, average 9.00 in the database)

What people dislike

Very heavy (the f/1.8 exceeds 800g), dwarfing most cameras
Extremely stiff, non-rubberized focus dial that requires the whole hand to rack focus
Long minimum focus distance (~1.7m on the f/1.8) limiting tight portraits
Softness and abundance of aberrations wide open
Difficult critical focus due to razor-thin depth of field

Pro Tips

Use it deliberately for portraits where its dreamy, creamy softness is a feature, not a flaw
Shoot in shade or controlled/artificial light to preserve contrast, as open sunlight can induce a foggy contrast drop (per the f/1.8 reviews)
Take your time focusing — the thin depth of field and stiff focus dial demand careful manual focus
Embrace or correct the mild vignette in post as desired

Sources (1)

Web-grounded synthesissecondary

The reviews provided actually document the Porst Tele Auto 135mm f/1.8 (a superfast MF portrait lens), not the f/2.8 variant requested here, so specifics for the f/2.8 are unknown. According to the Pentax Forums database entry, the branding 'Porst' was applied to a lens family made by Mitake, using a 5-element/4-group optical design that was rebranded across a bewildering range of names: Spiratone Plura-Coat, Computar, Promura, Kenlock, Formula 5, Eyemik, Apollo, Ultra-Unitor, Accura, Varo, Vivitar and Weltblick. Porst itself was a German photographic retailer that sold rebadged Japanese optics under its own name. At least four distinct optical designs existed for the 135mm f/1.8 class before Pentax released its own SMC-A 135mm f/1.8. No established nicknames or community jargon (such as 'Bokeh King' or 'Iron Curtain') are evidenced in the reviews for this lens. The lens is loved for its dreamy, painterly portrait rendering born of its huge aperture and soft optical character.

https://www.pentaxforums.com/userreviews/porst-135mm-f1-8-tele-mc.htmlhttps://www.thelightmixer.com/blog/2021/3/10/porst-tele-auto-135mm-f18