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Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (FUJIFILM X, Neutral Flares)

BH #SI40AF133XXN • MFR #40AF133X-XN
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Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (FUJIFILM X, Neutral Flares)
90-Second Intro
Key Features
  • Covers Super 35 | T1.8-T22 Aperture
  • Selectable Manual and Autofocus
  • Neutral Streak Flares
  • Creates 2.35:1 Aspect Ratio in 16:9
Capture cinematic widescreen footage with the aid of an autofocus option using the Sirui FUJIFILM X-mount 40mm T1.8 1.33x S35 AF Anamorphic Lens. This innovative prime lens uses an STM motor for fast, accurate autofocus while offering manual focus for more complicated shots handled by a camera assistant/focus puller. It produces neutral flares that are a classic feature of the anamorphic format and has a fast T1.8 maximum aperture lens that is ideal for low-light capture and for creating distinctive bokeh effects.
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Sirui 40mm T1.8 Anamorphic AF Overview

Manual and Autofocus Anamorphic Prime
Capture cinematic widescreen footage with the aid of an autofocus option using the Sirui FUJIFILM X-mount 40mm T1.8 1.33x S35 AF Anamorphic Lens. This innovative prime lens uses an STM motor for fast, accurate autofocus while offering manual focus for more complicated shots handled by a camera assistant/focus puller. It produces neutral flares that are a classic feature of the anamorphic format and has a fast T1.8 maximum aperture lens that is ideal for low-light capture and for creating distinctive bokeh effects.
Super 35 Coverage
  • This anamorphic prime lens has a 1.33x squeeze factor.
  • It produces a widescreen 2.35:1 aspect ratio when shooting in a 16:9 mode.
Manual and Autofocus
  • The autofocus feature now lets you capture anamorphic footage as quickly as when using spherical lenses.
  • Select manual or autofocus using the switch on the lens.
  • Use the AFL button to lock the autofocus or create a custom setting.
High Optical Performance
  • One aspherical and five cylindrical elements contribute to the high optical quality of this lens.
  • Focus breathing and chromatic aberration are well controlled.
  • Supports EXIF metadata transfer and has a USB-C port for firmware upgrading.
Ideal for Low-Light Shooting
  • The maximum T1.8 aperture enables you to capture low-light scenes using lower camera ISO settings.
  • Choose between stepped and stepless aperture settings for smooth exposure adjustments.
  • Sharpness and optical quality are maintained even in night scenes.
Flares and Distinctive Bokeh
  • Shoot with a wide-open aperture to create a distinctive hexagonal bokeh.
  • Stop down to get an oval bokeh that is typical of the anamorphic look.
  • Create notable neutral flares that can be varied using different light sources.
All Around Prime
  • This all-around 40mm lens is ideal for portraits, landscapes, street scenes, and establishing shots.
  • Horizontally equivalent to 42mm in full-frame format.
Compact Cine-Style Form
  • This prime lens features a compact, lightweight design suitable for handheld and gimbal work.
  • Cine-style features include an 80mm front outside diameter, standard 0.8 MOD gears, and wide 360° focus rotation.
EAN: 6952060075860

Sirui 40mm T1.8 Anamorphic AF Specs

Key Specs
Focal Length
40mm
Maximum Aperture
T1.8
Lens Mount
FUJIFILM X
Lens Format Coverage
Super35/APS-C (37 mm Image Circle)
Filter Thread
77 mm x 0.75
Image Stabilization
No
Electronic Communication
Yes
Focal Length
40mm
Maximum Aperture
T1.8
Minimum Aperture
T22
Lens Mount
FUJIFILM X
Horizontal Squeeze (Anamorphic)
1.33x
Flare Color
Neutral
Lens Format Coverage
Super35/APS-C (37 mm Image Circle)
Angle of View
Super 35
Horizontal: 55°
Vertical: 25.4°
Optical Design
16 Elements in 12 Groups
Filter Thread
77 mm x 0.75
Minimum Focus Distance
1.97' / 60.05 cm
Aperture/Iris Blades
11
Image Stabilization
No
Gear Standard
0.8 MOD
Gear Rotation
Focus: 360°
Electronic Communication
Yes
Camera Connection
Flat Contacts (EXIF) Data
Diameter
Front: 3.1" / 80 mm
Length
Not Specified by Manufacturer
Weight
1.4 lb / 614 g
Packaging Info
Package Weight
3.025 lb
Box Dimensions (LxWxH)
8.5 x 6.7 x 6"

Sirui 40mm T1.8 Anamorphic AF Reviews

Nice

By Merabi
Rated 5 out of 5
Date: 2026-09-07

Nice

Made me Love Anamorphic

By Cory Ross
Rated 4 out of 5
Date: 2025-06-12

How did I go this long not using Anamorphic Lenses now I see how some of my favorite films where made. I absolutely love this lens paired with my Sony FX3. Now you do get a slight vignetting effect in some low light situations but its not that bad honest gives your footage a little character. Only thing about this lens that can be a bit of a challenge is the need to hunt at times. You have to keep that distance or it will hunt. However still for the price and the quality its not a deal breaker. Also Sirui already did one update that may do more in the future. I will Love this Lens. I will be getting the 20MM as well.

See any errors on this page?

When mounted on a Fujifilm X body are you be able ...

When mounted on a Fujifilm X body are you be able to see both "Body" and "Lens" firmware versions?
Asked by: Gary
Only native Fuji lenses will display their firmware version in the camera menu. Third-party lenses, such as the Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (FUJIFILM X, Neutral Flares), will not show firmware information in the camera’s menu.
Answered by: Chris H
Date published: 2025-07-05

On an APS-C camera, such as the Sony FX30, what ...

On an APS-C camera, such as the Sony FX30, what would be the equivalent focal length of this 40mm Sirui Anamorphic Lens?
Asked by: Craig
The Sirui 40 mm T1.8 1.33x S35 AF Anamorphic Lens (Sony E, Neutral Flares) would have a 60 mm view on the APS-C sensor of the Sony FX30.
Answered by: Chris H
Date published: 2025-09-01

I am not seeing Nikon Full Frame cameras showing ...

I am not seeing Nikon Full Frame cameras showing up as "compatible" to this lens. I have cameras like Z6III. Why is that?
Asked by: Taka
The Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (Sony E, Blue Flares) is an S35 lens and will not support a full-frame camera. However, most cameras have APS-C or S35 modes, and if you use your camera in crop sensor mode, the lens will work. Also, make sure to purchase the Z-mount lens model. See below: Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (Nikon Z, Blue Flares), BH # SI40AF133XZB
Answered by: Elliot A
Date published: 2025-11-03

Can this lens (in any of its formats) be adapted ...

Can this lens (in any of its formats) be adapted to a Canon RF camera?
Asked by: Craig
No, unfortunately, the Sirui 40 mm T1.8 1.33x S35 AF Anamorphic Lens in Leica L, Sony E, Nikon Z, FUJIFILM X, or Micro Four Thirds does not adapt to or have an adapter for connecting to an RF-mount camera.
Answered by: Elliot
Date published: 2025-06-12

The angle of view specs for the MFT version are ...

The angle of view specs for the MFT version are the same as the E-mount version. Is the MFT crop factor taken into account here?
Asked by: David
When using the Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (Micro Four Thirds, Neutral Flares) and all other lenses, the focal length of a lens does not change when used on a different system; it is the field of view compared to a full frame that changes. Crop factor compared to 35mm equivalent is only relevant when comparing to full frame.
Answered by: Elliot
Date published: 2025-09-01

Is this compatible with the Z-Mount Red Komodo X?

Is this compatible with the Z-Mount Red Komodo X?
Asked by: Daniel
The actual answer is "not yet" - Sirui has not released the appropriate firmware for this to work on the Komodo-X Z-mount (their response to me). The lens will mount, but will have no power and will not be recognized by the KX. Without power, the iris is stuck at f/22, cannot be adjusted, and the lens cannot even be manually focused.
Answered by: Ron
Date published: 2025-07-12

Can you change the mount like you can do on some ...

Can you change the mount like you can do on some of the Siri?
Asked by: Paul
The mount of the Sirui 40mm T1.8 1.33x S35 AF Anamorphic Lens (Leica L, Blue Flares) cannot be changed or swapped.
Answered by: John W
Date published: 2025-08-11

Is the color coding on the neutral flare lens silv

Is the color coding on the neutral flare lens silver on the body like the 20mm, or is it blue like shown??
Asked by: Maurice
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