Porst Tele E 135 mm f/ 1.8 - fast fixed focal length telephoto lens for a 35mm SLR with the M42 screw mount.
Lens has a Sonnar optical system design. Sufficiently close analogue by optical design of the famous Olympia Sonnar 180/2.8.
Porst is a German lens distributor company so it simply placed it's brand on lenses. According to one version, the manufacturer of the lens Porst Tele E 135 mm f / 1.8 was the Japanese optical company Tomioka Kōgaku KK (Now Kyocera Optec Co., Ltd.).
Lenses similar by optical system design were manufactured with the brand names: Samigon, Soligor, Polaris, Weltblick, Sigmatel and some other with the m42 screw mount and removable shank.
Lens Porst Tele E 135 mm f / 1.8 has a rare (but not best and unique) speed for a 135mm lens. There were faster lenses like Nortiar 135 mm f / 1.4 which weight is 3kg.
An image produced by Porst Tele E 135 mm f / 1.8 lens is sharp even from F1.8 and has good 3D-effect at the wide-open aperture. Bokeh is smooth and harmonious. Contrast is above average.
This lens is not flare-resistant and suffers from backlight. The problem occurs cause of a big size of the front element. It is not being recessed enough. Lens Hood is highly recommended.
Focusing ring on Porst Tele E 135 mm f / 1.8 lens is large and comfortable to use. Smooth rotation allows to focus quickly. But an aperture ring is small and it is located very close to the camera thus making work with this ring uncomfortable.
The lens is quite heavy and big . It is well balanced if camera has a battery grip.
Porst Tele E 135 mm f / 1.8 is an excellent choice for a portrait work, nature photography and any other artistic photography which requires a shallow depth of field.