SIRUI Auto Focus 20mm T1.8 Anamorphic Cine Overview
Combining the cinematic quality of 2.35:1 widescreen imagery with the convenience of subject-tracking autofocus, this SIRUI 20mm T1.8 1.33x S35 AF Anamorphic Lens is a versatile, wide-angle lens designed specifically for cameras with Super 35 sensors. With a 1.33x squeeze factor and T1.8 maximum aperture, the lens ensures exceptional low-light performance and allows for stunning subject isolation with its signature oval-shaped bokeh.
Powered by a precision STM stepping motor, the SIRUI 20mm delivers smooth, accurate, and quiet autofocus—a rare feature in anamorphic lenses. With eye-tracking capability and buttons for both focus mode and autofocus lock, the lens provides complete creative control. A female USB-C port enables firmware updates, ensuring lasting performance. Compact and lightweight, the lens fits advanced technology and visual quality into a form factor ideal for handheld, gimbal, and run-and-gun shooting, making it a powerful tool for independent creators and professional productions.
Anamorphic Aesthetic
- 1.33x squeeze factor for 2.35:1 images in 16:9 mode
- Unique oval bokeh enhances subject separation and depth
- Horizontal field of view equivalent to 22mm full-frame lens
- Blue lens flares for cinematic effect
Optical Performance
- 37mm image circle covers Super 35 sensors or full-frame with vignette
- T1.8 to T22 aperture for low-light performance and depth of field control
- 39 cm minimum focus distance for close-up shots
- Aspherical lens element minimizes chromatic aberration
Advanced Autofocus
- STM stepping motor for smooth, silent autofocus
- Eye-tracking autofocus for reliable subject tracking
- AF/MF switch to toggle between autofocus and manual focus
- AF-Lock button to hold focus or recall custom focus settings
Practical Design
- Uniform gear positioning with SIRUI 40mm AF Anamorphic Lens
- Compact (~9.6 cm long) and lightweight at around 0.5 kg
- 360° focus throw with standard gearing
Versatile Compatibility
- Compatible with mirrorless cameras
- Standard 77mm front filter thread
- Update lens firmware via female UCB-C port
SIRUI Auto Focus 20mm T1.8 Anamorphic Cine Lens Specifications
Key Specs
| Focal Length | 20 mm |
| Maximum Aperture | T1.8 |
| Lens Format Coverage | Super35 / APS-C |
| Filter Thread | 77 mm x 0.75 |
| Image Stabilization | No |
| Electronic Communication | Yes |
Aperture & Optical Design
| Maximum Aperture | T1.8 |
| Minimum Aperture | T22 |
| Interchangeable Mount | No |
| Horizontal Squeeze (Anamorphic) | 1.33x |
| Image Circle | 37.0 mm |
| Angle of View (Super 35) | Horizontal: 85.6° Vertical: 44.2° |
| Optical Design | 16 Elements in 12 Groups |
| Diaphragm Blades | 11 |
| Coating | Multi-Coated |
Focusing & Control
| Minimum Focus Distance | 0.4 m |
| Gear Standard | 0.8 MOD |
| Gear Rotation | Focus: 360° |
| Camera Connection | 1 x USB-C (Firmware Updates) |
Physical Specs
| Diameter | Focus Ring: 86.4 mm Iris Ring: 80 mm |
| Length | ~ 92.95 mm |
| Weight | ~ 500 g |
What's in the box
- 1 x SIRUI 20mm T1.8 1.33x S35 AF Anamorphic Lens
- 1 x Carrying Pouch
- 1 x Carrying Strap
- 1 x Front Lens Cap
- 1 x Back Lens Cap
- Barcode: 78877
- UPC Barcode: 6952060076454
- Supplier Code: 20AF133X-MN