Mamiya-Sekor SF C 150mm f/4 Soft Focus Lens for RB67 System

The Mamiya-Sekor SF C 150mm f/4 is a legendary special-application telephoto lens designed for the Mamiya RB67 medium format system. Highly prized by portrait and wedding photographers, this lens features controllable soft focus via designed-in spherical aberration. By using the included diffusion discs at apertures from f/4 to f/6.3, you can achieve a signature "glow" while maintaining a sharp underlying core. When stopped down to f/8 or smaller, the lens bypasses the soft-focus effect to deliver exceptionally sharp, traditional telephoto images.

Product Highlights

• Variable soft focus effect perfect for flattering skin tones and ethereal highlights.
• Multi-coated (C) optics for improved contrast and reduced flare.
• Integrated Seiko #1 mechanical leaf shutter with full flash sync at all speeds.
• Robust all-metal construction built for professional studio and field use.

Technical Specifications

• Lens Mount: Mamiya RB Bayonet (Compatible with Pro, Pro-S, and Pro-SD bodies)
• Focal Length: 150mm (Approx. 75mm equivalent in 35mm format)
• Aperture Range: f/4 to f/32
• Shutter Speed Range: 1 second to 1/400 second plus T (Time)
• Optical Construction: 5 elements in 3 groups
• Filter Size: 77mm
• Minimum Focus Distance: Approximately 615mm
• Weight: 790g
• Dimensions: 94mm length x 84mm diameter
• Year of Production: Introduced circa 1977

Condition Report

This lens is in excellent vintage condition. The optics are clear and brilliant with no fungus, haze, or separation. Minimal internal dust is present, which is typical for a lens of this age and does not affect image quality. The mechanical shutter is fully operational, with speeds sounding accurate to the ear. The aperture and focus rings move smoothly without resistance. The barrel shows light cosmetic wear consistent with professional use.

Package Includes

• Mamiya-Sekor SF C 150mm f/4 Lens
• Genuine Mamiya Front and Rear Lens Caps