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4:3 Sensor Mode
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4:3 Sensor Mode

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anamorphic open gate sensor mode cinemascope arri alexa

Sensor recording mode in classic 4:3 format (1.33:1)—primarily used for anamorphic capture, as 2x squeeze creates 2.66:1 image.

What is 4:3 Mode?

4:3 Mode is a sensor recording mode in digital cameras that utilizes the classic 4:3 aspect ratio (1.33:1). It is primarily used for anamorphic shooting, as a 2x anamorphic squeeze from 4:3 creates a 2.66:1 image.

Technical Background

ParameterValue
Aspect Ratio4:3 (1.33:1)
With 2x Anamorphic2.66:1 (cropped to 2.40:1)
UsageAnamorphic Shooting
Sensor AreaReduced vs. Open Gate

Comparison of Sensor Modes (ARRI Alexa LF)

ModeAspect RatioResolutionUsage
Open Gate1.44:14448x3096Spherical, Max. Flexibility
LF 2.39:12.39:14448x1856Spherical Scope
4:31.33:13414x2198Anamorphic
16:91.78:13840x2160TV/Streaming

Why 4:3 for Anamorphic?

AspectExplanation
Sensor UtilizationUtilize full height
2x Squeeze4:3 → 2.66:1
Classic LookLike 35mm Anamorphic
BokehOval bokeh emphasized

Mathematics

CalculationResult
4:3 = 1.33:1Recording Format
1.33 × 2 = 2.66After De-Squeeze
2.66 → 2.40Final Crop

Cameras with 4:3 Mode

Camera4:3 Resolution
ARRI Alexa Mini2.8K
ARRI Alexa LF3.4K
RED Komodo4K (6:5)
Sony Venice4K

Workflow

On Set

StepDescription
Select Mode4:3 in camera
MonitoringView De-Squeezed
FramingCompose for 2.40:1

Post-Production

PhaseActivity
ImportSqueezed 4:3
De-SqueezeStretch 2x horizontally
CropCrop to 2.40:1
DeliveryFinal Scope Image

Advantages

AdvantageDescription
Classic LookLike Film Anamorphic
Full HeightMore vertical resolution
BokehMaximum anamorphic character

Disadvantages

DisadvantageDescription
Less ResolutionVs. Open Gate
No ReframingLittle room for maneuver in post
Lenses NeededExpensive anamorphic lenses

Today

4:3 Mode is the standard for anamorphic digital production. Anyone who wants the classic scope look with modern cameras works in 4:3 with 2x anamorphic lenses.

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