Rokinon 20mm f/1.8 ED AS UMC Lens for Pentax K

Rokinon 20mm f/1.8 ED AS UMC Lens for Pentax K

Rokinon 20mm f/1.8 ED AS UMC Lens for Pentax K

B&H # RO2018PK MFR # RK20M-P
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Product Highlights

  • K-Mount Lens/Full-Frame Format
  • Aperture Range: f/1.8 to f/22
  • Two Aspherical and Three ED Elements
  • Ultra Multi-Coating
  • Manual Focus Design
  • Rounded Seven-Blade Diaphragm
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Reg. Price: $549.00

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Rokinon 20mm f/1.8 overview

  • 1Description

Designed for Pentax K-mount DSLRs, this 20mm f/1.8 ED AS UMC Lens from Rokinon is a bright wide-angle prime featuring an intuitive manual focus design and enhanced optical construction. Two aspherical elements and three extra-low dispersion elements are used to reduce both spherical and chromatic aberrations for greater sharpness, clarity, and reduced distortion. The optics also feature an Ultra Multi-Coating to guard against lens flare and ghosting for increased contrast and color neutrality when working in strong lighting conditions. The manual focus operation affords working with subjects as close as 7.9" away, and a rounded seven-blade diaphragm contributes to a pleasing bokeh quality.

A wide-angle prime designed for full-frame Pentax K-mount DSLR cameras, this 20mm f/1.8 lens can also be used on APS-C models where it will provide a 30mm equivalent focal length.
Bright f/1.8 maximum aperture benefits working in low-light conditions and also affords greater control over depth of field for selective focus control.
Two aspherical elements are used to reduce spherical aberrations for increased sharpness and minimized distortion.
Three extra-low dispersion elements help to control chromatic aberrations and color fringing for improved clarity and color fidelity.
An Ultra Multi-Coating has been applied to individual elements in order to reduce flare and ghosting for increased contrast and a neutral color balance.
Manual focus operation allows for precise control with a minimum focusing distance of 7.9".
Rounded seven-blade diaphragm contributes to a smooth and pleasing bokeh quality.
UPC: 084438765359
In the Box
Rokinon 20mm f/1.8 ED AS UMC Lens for Pentax K
  • Front and Rear Lens Caps
  • Limited 1-Year Warranty
  • Table of Contents
    • 1Description

    Rokinon 20mm f/1.8 specs

    Focal Length 20mm
    Aperture Maximum: f/1.8
    Minimum: f/22
    Camera Mount Type Pentax K
    Format Compatibility 35mm Film / Full-Frame Digital Sensor
    Angle of View 94.8°
    Minimum Focus Distance 7.87" / 20 cm
    Optical Design 13 Elements in 12 Groups
    Diaphragm Blades 7, Rounded
    Autofocus No
    Filter Thread Front: 77 mm
    Dimensions (DxL) 3.27 x 3.42" / 83.0 x 86.9 mm
    Weight 1.08 lb / 493 g
    Packaging Info
    Package Weight 1.6 lb
    Box Dimensions (LxWxH) 7.1 x 5.2 x 5.1"

    Rokinon 20mm f/1.8 reviews

    20mm f/1.8 ED AS UMC Lens for Pentax K is rated 4.7 out of 5 by 3.
    Rated 5 out of 5 by from Fantastic wide angle When I switched from Nikon to Pentax, I knew the one focal length I would have trouble covering is wide angle... Pentax simply doesn't have any full frame wides. The only viable option is the Pentax 15-30mm which is an exceptional lens, but it's expensive and doesn't take filters. I need a relatively inexpensive wide for landscape and long exposure work. The Rokinon has performed really well. Even wide open at 1.8 it was sharper than I expected. At f/5.6 through f/11 it's been fantastic. Corners, edges, mid frame and center have all been great. It's built well (doesn't feel shoddy) and the threads easily take my Formatt-Hitech filter adapter. The one area I haven't tested yet is astrophotography re: coma. The few night shots I have taken so far (with those rare clear skies), the stars looked great, but they weren't near the edge of the frame and I wasn't pixel peeping for coma. Besides, for astro work I'd probably go with the Rokinon 24mm, which is highly regarded for night shooting. Overall I'm borderline thrilled with this lens -- it hasn't left my camera body in the few weeks that I've owned it.
    Date published: 2017-01-24
    Rated 5 out of 5 by from Very nice ultra-wide for the K1. I used this lens all day on a Pentax K1. For those who haven't used K-mount Rokinons it acts like an A lens. It gives a nice wide FOV for locations where foot zooming back is not possible. It provided high-contrast and sharp images. I was manual focusing with the illuminated AF pts in the OVF as confirmation. This worked very well and accomplished fine focus. Mostly indoors in ambient light with shutters under 1/20 and SR turned on. Sr worked very well but a 20mm isn't hard to hand hold in any case. I haven't tried landscape or astro-photography yet but I like what I've seen so far.
    Date published: 2017-03-20
    Rated 4 out of 5 by from Better Than Expected Was searching for a high quality (Zeiss, Sigma Art) Prime Wide Angle (18-21mm) for Pentax K-1 with no luck. After reading good reviews, settled for Rokinon 20mm F1.8 (K-1 shows 1.7). Lens is well made, light weight and compact. I see little/no difference in sharpness of same pictures/settings taken with my other camera/lens being Canon 5DM4 w/Canon16-35L F4 IS. I prefer Auto Focus but Manual Focusing via Live View seems to be more accurate. Rokinon was not what I was looking for but has so far has been a pleasant surprise for a lot less!
    Date published: 2018-02-15
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    Rokinon 20mm f/1.8 Q&A

    Rokinon 20mm f/1.8 accessories

    Designed for use with:

    • Pentax K-1
    • Pentax K-1 II
    • Pentax K-3 II
    • Pentax K-70
    • Pentax K-S2
    • Pentax KP
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