INON UCL-90 M67 Underwater Close-Up Macro Lens | +11 Diopter Wet Lens with Long Working Distance

Strong Magnification Without Extreme Handling Demands

Close-up lenses shorten the minimum focusing distance of the camera’s master lens, allowing small subjects to appear significantly larger in the frame. The UCL-90 M67 provides enough magnification for nudibranchs, shrimp, pygmy seahorses, blennies, coral polyps, juvenile fish, and other small marine subjects while remaining more manageable than an extremely powerful super-macro diopter.

Its 90mm underwater focal length is equivalent to approximately +11 diopters. This gives photographers a useful balance of magnification, focusing range, depth of field, and lighting access.

Up to 2.23x Magnification

When used with the AF-S VR Micro-Nikkor 105mm f/2.8G IF-ED on a compatible full-frame underwater system, the UCL-90 can provide maximum magnification of approximately 2.23x at the master lens’s minimum focusing distance. This represents an image-area ratio of approximately 4.98x.

This level of magnification is well suited to filling the frame with small animals and fine anatomical details without creating the extremely short working distance associated with more powerful super-macro lenses. Actual magnification varies by camera, master lens, housing port, focus position, and lens-to-port spacing.

Longer Working Distance for Easier Lighting

The UCL-90 M67 is designed to maintain a comfortable working distance while delivering strong magnification. With the referenced 105mm macro configuration at minimum focus, the distance from the front of the close-up lens to the subject is approximately 69mm / 2.71 inches.

This additional space makes it easier to place strobes, snoots, and focus lights without the lens body blocking the light path. It also helps photographers approach cautious subjects without placing the housing directly against them.

High Image Quality Throughout the Focusing Range

The UCL-90 is optically designed exclusively for use underwater. Its optical formula helps suppress aberrations throughout the supported focusing range, delivering sharp, high-contrast images at different subject distances.

This consistent performance is especially important in macro photography, where color fringing, softness, and reduced contrast become increasingly visible as magnification rises.

Compact High-Refractive-Index Glass Design

High-refractive-index optical glass allows INON to produce strong +11 diopter performance in a relatively compact lens body. The smaller design creates less obstruction around the front of the housing port and gives photographers greater freedom when arranging underwater lighting.

The lens consists of three elements arranged in two groups, providing a balance of compact size, controlled aberration, practical working distance, and high magnification.

Achromatic Optics for Cleaner Detail

The UCL-90 M67 incorporates an achromatic optical element to reduce chromatic aberration. This helps minimize unwanted colored fringes around fine details such as nudibranch rhinophores, shrimp antennae, fish eyes, and textured coral surfaces.

Anti-reflection coatings on all lens surfaces also help suppress flare and ghosting while preserving image contrast and fine detail.

Where the UCL-90 Fits in the INON Macro Range

For many photographers, the UCL-90 offers the most versatile middle ground. It provides a noticeable increase in magnification over the UCL-165 while remaining easier to light and focus than the more powerful UCL-67.

Broad Camera and Lens Support

The compact optical design supports a wide range of compatible underwater systems, including full-frame macro lenses, APS-C macro lenses, Micro Four Thirds lenses, mirrorless standard zooms, and selected compact cameras.

Direct M67 Mounting

The UCL-90 uses the widely adopted M67 screw mount and can attach directly to compatible threaded housing ports and adapters. This versatile mounting format is commonly used on compact, mirrorless, and interchangeable-lens underwater camera systems.

A threaded mount provides a secure connection, while compatible flip adapters can offer faster access when the photographer needs to alternate between standard macro and higher-magnification shooting during the same dive.

Optional Flip-Mount Configuration

The original threaded mount can be replaced with the separately available INON M67 Flip Mount Adapter designed for compatible UCL-67 and UCL-90 configurations. This allows the lens to be used with selected flip holders, including compatible Nauticam-style systems.

A properly configured flip mount positions the close-up lens near the housing port and allows it to be moved into or out of the optical path without completely removing it underwater.

Lens Stacking for Advanced Super Macro

Selected lower-powered INON M67 close-up lenses may be stacked using the appropriate separately sold front adapter. This can provide additional magnification for very small subjects and advanced super-macro applications.

• Selected configurations may support the INON UCL-165 M67
• Selected configurations may support the INON UCL-330
• The required adapter and mounting parts are sold separately
• Compatibility should be confirmed for the complete lens configuration

Designed Exclusively for Underwater Use

The UCL-90 M67 is optically corrected for use underwater. Its intended magnification, aberration control, and image quality depend on the optical properties of water.

On land, the lens may provide little or no useful magnification and can produce edge distortion, vignetting, and reduced image quality. It should be treated as a dedicated underwater optical accessory.

Compatibility

• Compatible 60mm–100mm macro lenses for full-frame systems
• Compatible 40mm–60mm dedicated macro lenses for APS-C systems
• Compatible 45mm–60mm macro lenses for Micro Four Thirds systems
• Selected Micro Four Thirds standard zoom lenses
• Selected compact cameras with maximum optical zoom of 5x or less
• Requires a compatible M67 threaded port, adapter, or flip holder

Lighting and Depth-of-Field Considerations

Depending on the housing, working distance, and angle of view, the close-up lens may block part of the camera’s built-in flash. An external underwater strobe, video light, or focus light is recommended for more consistent illumination.

Maximum magnification is generally achieved near the telephoto end of a compatible zoom lens. As magnification increases, depth of field becomes progressively shallower, making accurate focus, stable buoyancy, careful camera movement, and appropriate aperture selection increasingly important.

Technical Specifications

What's in the Box

• INON UCL-90 M67 Underwater Close-Up Lens
• Front lens cap
• Rear lens cap
• User documentation