Conversion lenses

Conversion Lenses for Underwater Macro and Wide-Angle Photography

Conversion lenses, also referred to as wet lenses, mount externally to underwater housing ports via threaded or bayonet fittings. They allow photographers to change between macro and wide-angle perspectives during a dive without opening the housing. Some manufacturers specialise in advanced optical systems, such as Nauticam conversion lenses.

Wet lenses extend the optical capabilities of compact and mirrorless systems by increasing magnification or expanding field of view, depending on the lens type.

Wet Macro Lenses for Close-Up Imaging

Wet macro lenses increase magnification beyond the capability of a standard flat port. Higher dioptre values provide greater magnification but reduce working distance. Some systems allow stacking multiple macro wet lenses for additional magnification.

Wide-Angle Wet Lenses and Converters

Wide-angle converters expand the field of view for photographing reefscapes, schools of fish, or large structures. They help reduce distortion caused by water refraction.

Many wide-angle wet lenses use bayonet fittings for quick attachment. This allows fast switching between macro and wide-angle perspectives during a single dive.

Mounting Standards: M52 and M67 Threads

Conversion lenses are available in standard thread sizes, most commonly M52 and M67. Matching the correct thread ensures stable mounting and optical alignment with the housing port.

For even greater flexibility, conversion lenses can be mounted on flip adapters, allowing divers to swing lenses in and out of position quickly during a dive.

Adapters are also available for housings that use alternative fittings, making these lenses compatible with a wide range of systems.

• External wet optics attach to housing ports
• Enable macro or wide-angle imaging
• Mount via M52 or M67 threads
• Support both compact and mirrorless systems
• Allow quick lens changes during a dive

Choosing the Right Conversion Lens

Selecting a suitable conversion lens depends on housing port type, thread size (M52 or M67), lens configuration and intended shooting distance. Macro wet lenses increase magnification for close-up subjects, while wide-angle wet lenses expand field of view for larger scenes.

Compatibility between housing port, adapter system and lens mount should be verified before use. For additional technical guidance on working distance, dioptre strength and wet lens handling underwater, refer to the detailed resources available in our knowledge section.

Learn more about wet lenses

• Wide-angle underwater photography explained
• Using wet lenses with your standard lens underwater

Questions about conversion lenses

What is a conversion lens in underwater photography?

A conversion lens, also known as a wet lens, is an external optic mounted to the front of an underwater housing port. It allows you to increase magnification for macro photography or expand the field of view for wide-angle scenes without opening the housing.

What is the difference between a macro wet lens and a wide-angle wet lens?

A macro wet lens increases magnification for small subjects such as nudibranchs or shrimp. A wide-angle wet lens expands the field of view, making it suitable for reef scenes, wrecks and larger marine life.

Can you switch wet lenses during a dive?

Yes. Many wet lenses are designed to be attached or removed underwater. Systems with bayonet mounts or flip adapters make switching between lenses quick and easy during a dive.

What is the difference between M52 and M67 threads?

M52 and M67 refer to the thread size used to mount the lens to the housing port or adapter. Using the correct thread size ensures proper fit and stability.

Do wet lenses work on every underwater housing?

Not always. Compatibility depends on the housing port, thread size and adapter system. It is important to check whether a wet lens matches your setup.