Simmod Circular Close-Up Diopter (95mm, +1/2)

Minimum focus distance is one of the primary limitations of many cinema and vintage lenses. A diopter changes the optical focal range of the lens, allowing closer focus while maintaining the original rendering characteristics of the lens system.

The Simmod 95mm Circular Close-Up Diopter is a screw-in optical filter designed for close-focus imaging on cine and photographic lenses with a 95mm filter thread.

Filter Format

• Rear thread size: 95mm
• Front thread size: 95mm
• Available strengths:
  • +0.5
  • +1.0
  • +2.0

The front and rear threading allow additional filters to be mounted or stacked when required.

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 characteristics of the original lens remain intact, including:

• Contrast behavior
• Lens flare characteristics
• Depth rendering
• Focal compression

The system is compatible with:

• Spherical lenses
• Anamorphic lenses

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

Optical Construction

• Manufactured using Schott BK7 optical glass
• 14-layer multi-resistant nano coating applied to both sides
• Designed to minimize:
  • Reflections
  • Ghosting
  • Contrast reduction

The optical glass index is selected to align closely with cine lens optical characteristics.

Mechanical Construction

• Electroplated brass filter ring
• Precision-threaded front and rear interfaces
• Matte black internal finish

The brass construction is designed to reduce thread deformation and minimize the likelihood of thread binding during repeated installation and removal.

Mechanical Performance

• Screw-in threaded installation
• Maintains consistent filter alignment
• Compatible with matte box operation when sufficient clearance exists
• Lightweight construction suitable for photo and compact cine lenses

The dual-threaded structure also allows filters to remain stacked during transport if required.

System Behavior

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

Included Components

• Circular close-up diopter
• Felt storage case
• Aluminum identification tag

Notes

• Requires 95mm front filter thread compatibility
• Step rings may be used for smaller lens thread sizes
• Proper support is recommended when stacking multiple filters or using heavy matte box configurations