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SIRUI Astra 50mm review

Why this lens matters

Traditional full-frame anamorphic cinema lenses have commonly relied on manual focusing and more involved production workflows. The SIRUI Astra introduces autofocus, electronic communication and practical physical controls while retaining the stretched image, flare behaviour and wider presentation associated with anamorphic filmmaking.

For owner-operators, content creators, documentary filmmakers and smaller production teams, the appeal is simple: it makes the anamorphic format easier to use without turning the lens into a lightweight photography-style prime.

01

Full-frame coverage

A 44mm image circle is designed to cover full-frame mirrorless sensors, allowing the Astra 50mm to work across the full imaging area of compatible cameras.

02

Autofocus workflow

The integrated STM focus motor supports autofocus operation, making the lens considerably more practical for solo filming, tracking shots and camera-to-subject movement.

03

Constant 1.33x squeeze

The constant squeeze factor creates a wider de-squeezed image while preserving the characteristic vertical stretch and anamorphic rendering throughout the focusing range.

04

Fast T1.8 aperture

The bright T1.8 maximum transmission supports lower-light filming, selective depth of field and stronger subject separation.

05

Cine-style controls

Geared focus and iris rings, an iris lock, AF/MF switch, function button and click or de-click aperture control provide a more production-focused layout.

06

Neutral flare option

The neutral-flare version keeps strong light sources looking more natural than the more stylised blue-flare alternative, making it well suited to travel, documentary and lifestyle work.

Understanding the image

What does 1.33x anamorphic mean?

An anamorphic lens optically compresses a wider horizontal field of view into the recorded frame. The footage is then de-squeezed for correct playback, revealing the intended widescreen image.

Widescreen without a simple crop

More horizontal information

When 16:9 footage recorded with a 1.33x lens is correctly de-squeezed, the result is approximately a 2.37:1 image. Rather than merely placing black bars over conventional footage, the lens captures additional horizontal scene information through optical compression.

Recognisable anamorphic rendering

Bokeh, flare and vertical stretch

The Astra produces the vertically stretched background rendering, oval-style bokeh and horizontal flare response associated with anamorphic imagery. The neutral-flare version used here delivers a more restrained and natural interpretation.

SIRUI Astra specifications

50mm L-mount technical details

These are the principal specifications for the SIRUI Astra 50mm T1.8 1.33x full-frame autofocus anamorphic lens. Weight and physical length can vary slightly by lens mount.

Lens type
Full-frame autofocus anamorphic cine lens
Focal length
50mm
Lens mount tested
L-mount on Panasonic LUMIX S5IIX
Squeeze factor
Constant 1.33x
Format coverage
Full frame with 44mm image circle
Aperture range
T1.8 to T22
Aperture blades
11
Optical construction
18 elements in 14 groups, including four cylindrical elements and one aspherical element
Focus system
Autofocus and manual focus with STM motor
Minimum focusing distance
0.5m / 1.64ft
Focus-ring rotation
Approximately 136 degrees
Filter thread
67mm
Front outer diameter
72mm
L-mount length
Approximately 128.9mm excluding lens cap
L-mount weight
Approximately 625g
Flare options
Neutral flare or blue flare
Construction
Aluminium-alloy exterior with dust, dirt and raindrop resistance

LUMIX S5IIX anamorphic workflow

A natural pairing for L-mount

The L-mount Astra 50mm attaches directly to the Panasonic LUMIX S5IIX without an adapter. The camera also provides a dedicated 1.33x anamorphic de-squeeze display, allowing you to monitor the composition in its corrected proportions while recording.

In-camera monitoring

Set the display to 1.33x

The de-squeeze display changes the monitoring view rather than permanently altering the recorded file. The footage can then be interpreted or de-squeezed in your editing software.

  • Select the 1.33x de-squeeze display in the monitor settings.
  • Save the setup to a custom camera mode for faster access.
  • Use focus peaking, AF or back-button focusing to suit the shot.

Real-world handling

Balanced for handheld filmmaking

At approximately 625g in L-mount, the lens feels substantial but remains manageable on the S5IIX. The geared rings also leave the option of adding a follow-focus system when building a larger rig.

  • 67mm front thread for circular ND or variable-ND filters.
  • Click or de-click the iris ring depending on the production.
  • Use the iris lock to prevent unintended aperture movement.

Initial assessment

Who is the Astra 50mm for?

The SIRUI Astra 50mm T1.8 is particularly compelling for creators who want a recognisable anamorphic image without committing to an entirely manual focusing workflow. Its autofocus, electronic iris operation and practical physical controls make it suitable for smaller crews and independent filmmakers.

The 50mm focal length is versatile enough for portraits, controlled handheld sequences, travel details, interviews and cinematic narrative coverage. The 0.5m minimum focusing distance also makes it more practical for close detail shots than many traditional anamorphic designs.

Solo filmmakers Autofocus reduces dependence on a dedicated focus puller.
LUMIX creators Native L-mount fitting and 1.33x in-camera monitoring.
Travel filmmakers A cinematic image in a relatively manageable package.
Small production teams Cine controls with a more efficient hybrid workflow.

SIRUI lens discounts FAQ

Frequently asked questions

Answers to the most common questions about the SIRUI Astra 50mm, L-mount compatibility, anamorphic de-squeeze and my current SIRUI lens discount.

Is there a SIRUI discount code?
Yes. Use discount code SONGHURST to receive 5% off eligible SIRUI lenses and gear. Shop through my SIRUI link here.
Does the SIRUI discount apply only to the Astra 50mm?
The code is intended for eligible SIRUI products rather than only this lens. Product eligibility and regional availability can vary, so confirm that the discount appears at checkout.
Is the SIRUI Astra 50mm a full-frame anamorphic lens?
Yes. The Astra 50mm has a 44mm image circle designed to cover full-frame mirrorless sensors.
Does the Astra 50mm have autofocus?
Yes. It uses an STM motor and provides both autofocus and manual focus operation through the AF/MF selector on the lens.
Does the Astra 50mm fit the Panasonic LUMIX S5IIX?
Yes, provided you select the L-mount version. It connects directly to the LUMIX S5IIX without a mount adapter.
Can the LUMIX S5IIX de-squeeze the 1.33x image?
The S5IIX offers a 1.33x anamorphic de-squeeze display for monitoring. This gives you a correctly proportioned preview while filming; the original recorded material can still require the appropriate anamorphic interpretation in post-production.
What is the filter size?
The SIRUI Astra 50mm uses a 67mm front filter thread, making it compatible with many commonly available ND and variable-ND filters.
Should I choose neutral flare or blue flare?
Neutral flare is the more restrained option for natural, travel, commercial and documentary imagery. Blue flare creates a stronger, more stylised science-fiction or urban-cinema effect.
Is this a review or sponsored advertisement?
The lens was provided for review, but the video and written observations reflect my own experience. Purchases through my link may generate an affiliate commission at no extra cost to you.

SIRUI lens discount

Save 5% on SIRUI lenses and filmmaking gear

Follow the link below and use my code at checkout. The offer provides an easy way to save on the SIRUI Astra 50mm T1.8 and other eligible SIRUI products.

SONGHURST
Shop SIRUI & Use Code SONGHURST

Affiliate link. Availability, pricing and discount eligibility can vary by product and region. Confirm the final price at checkout.