Nauticam Mid-range Focus Optimizer 3-II (MFO-3II)

Elevate your underwater macro photography with the Nauticam MFO-3II. 

Key Features

• Extend Working Distance and Field of View: Works well with 90–105 mm macro lenses (Canon RF/EF 100 mm, Nikon Z MC 105 mm, Sony FE 90 mm, etc.), converting a narrow ~23° field to ~38°. It increases the effective focus range from contact to 1.5 m, which is great for capturing subjects from tiny nudibranchs to larger critters.
   
• Maintain Image Sharpness and Contrast: The 4-element/3-group glass optics feature anti-reflection coatings, providing crisp, high-contrast images by minimizing the distortions commonly found with flat port usage.
   
• Boost Autofocus Reliability: By optimizing focus-through-glass, the MFO-3II significantly cuts down on focus hunting and improves autofocus consistency. This feature is particularly helpful in low-contrast or fluorescent-lit environments.
   
• Compact and Dive-Proof Design: Made from hard-anodized aluminum, it is rated for depths up to 100 m, weighs just 602 g (negative 120 g in water), and connects using standard M67 threads or Nauticam bayonet systems.
   
• Versatile Usage: Whether for blackwater sessions or reef macro photography, this optic eliminates the need for lens changes. For example, you can perfectly frame everything from a thumb-sized nudibranch to a grapefruit-sized frogfish with just one setup.

Technical Specifications

• Dimensions: Ø 84 mm × Height 114.2 mm
• Weight (in air): 602 g
• Underwater Buoyancy: –120 g (negatively buoyant)
• Maximum Magnification: 0.9×*
• Field of View: Native 23° / Converted 38°
• Working Distance: 0 to 1500 mm*
• Housing Material: Hard-anodized aluminum alloy
• Optical Construction: 4 elements in 3 groups
• Lens Coating: Multi-layer anti-reflection coating
• Mount Type: M67 threaded front
• Depth Rating: 100 m

*Tested with Nikon Nikkor Z MC 105mm f/2.8 VR S Macro Lens

In the Box

• Front and rear rubber caps
• Neoprene bag
• M67 Spacer ring for SMC/CMC
• Cleaning cloth

Version note: The current version is named MFO-3II. Serial numbers start from A680120. Functionality is unchanged, but the design and physical dimensions have been updated compared with the first version.