Simmod Diopter (4 x 5.65", +1)

Close-up imaging with cinema lenses is often limited by minimum focus distance.
A diopter changes the optical focal range of the lens, allowing closer focus while maintaining the original optical characteristics of the lens system.

Occupies two matte box filter stages due to element depth and curvature

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The Simmod 4 x 5.65 Close-Up Diopter is a tray-mounted close-up filter designed for use with industry-standard matte boxes and cinema lens systems.

Filter Format

• Filter size: 4 x 5.65 inches
• Available strengths:
  • +0.5
  • +1.0
  • +2.0

The filter is designed for use in matte box systems utilizing standard 4 x 5.65 filter trays.

Optical Function

The diopter reduces the minimum focus distance of the lens by introducing additional optical power in front of the lens.

This allows:

• Closer focus operation
• Increased image magnification
• Shallow depth-of-field close-up imaging

The optical behavior of the original lens is retained, including:

• Rendering characteristics
• Flare behavior
• Focal compression

The system is compatible with:

• Spherical lenses
• Anamorphic lenses

Diopters are commonly used with anamorphic optics to compensate for limited native close-focus capability.

Optical Construction

• Precision optical glass construction
• 14-layer nano and anti-reflective coatings applied to both sides
• Designed to minimize:
  • Reflections
  • Ghosting
  • Contrast loss

The +2.0 version utilizes an achromatic optical design to maintain image consistency and reduce chromatic aberration associated with thicker optical elements.

Mechanical Design

The optical element is mounted within a:

• Precision-machined aluminum tray frame
• 4 x 5.65 matte box format

Unlike systems utilizing smaller round optics mounted inside oversized trays, the optical element extends closer to the tray edges to maximize usable image area and reduce unnecessary material bulk.

Tray Configuration

• Occupies two matte box filter stages due to element depth and curvature
• Compatible with side-loading matte boxes
• Includes removable red anodized handling tab for filter insertion and removal

Matte boxes with divider bars between stages may not provide sufficient clearance.

Construction

• CNC-machined aluminum tray frame
• Optical glass element
• Matte black finish
• Removable anodized handling tab

The structure is designed to maintain rigidity while allowing rapid filter changes during operation.

System Behavior

• Fully passive optical filter system
• No electronic components
• Does not modify internal lens mechanics
• Effect intensity depends on:
  • Lens focal length
  • Aperture
  • Subject distance
  • Diopter strength

Notes

• Requires matte box compatibility with 4 x 5.65 filters
• Occupies two filter stages due to optical depth
• Proper support is recommended when stacking multiple filters