INON UWL H-100 Wide-Angle Wet Lens System Guide

UWL-h100 28m67
By Lisa Collins and Steve Warren, owners, INON UK

Wide-angle photography is an essential part of nearly all successful underwater photographers skills set. On land, we may use wide-angle techniques and equipment to shoot a large subject, like a building or inside a small space, such as a display in a museum. Similarly, underwater we may want to photograph the imposing bows of a shipwreck or inside a confined area, like the ships engine room. But we are also forced to use wide-angle photography methods in a completely different way to most terrestrial photographers because of the very restricted visibility in which we work. Even the worst fogbank rarely creates visibility as bad as the best underwater visibility and few land photographers choose to shoot in fogbanks. So we depend on wide-angle lenses to get close to our subject which improves colour, contrast and definition so dramatically it is often the difference between a completely useless soft focus, colourless, insipid snapshot and a keeper. We also use wide-angle lenses underwater for a creative effect that is little used topside – close focus, wide-angle and an extreme variation of close focus, wide-angle called wide angle macro.


For many underwater photographers who are starting out and on a budget, a wide-angle lens will be more useful than an underwater strobe. Many subjects can be photographed well using natural light. Key to taking good underwater photographs is getting close to your subject to reduce the problems that shooting through water create. These include colour loss, diffusion and scatter. The INON UK Level One Digital Underwater Photography Course explains these problems and how to overcome them in detail.

The INON UWL-H100 underwater wide-angle lens is a true wide-angle lens. It almost doubles the underwater field of view of a compact camera with a built in lens or compatible compact system camera interchangeable lens from around 56 degrees to 100. It not only greatly increases the field of view, it expands the depth of field, meaning much more of your picture will be in focus, reducing focusing errors and, combined with the ability to focus onto its own front lens, makes it easy to shoot creative close focus, wide-angle and wide angle macro underwater photographs. For those needing an even greater field of view, the INON UWL-H100 can be fitted with the matched INON Dome Lens Unit 11. This special accessory increases the UWL-H100’s field of view to around 150 degrees. Because the INON UWL-H100 is a ‘wet lens’ it can be changed underwater. This provides the flexibility to flit between your compact cameras or compact system cameras zoom lens for, say, photography of small to medium sized reef fish, add a close up lens to take macro pictures of a nudibranch or attach your INON UWL-H100 wide-angle lens to take a close focus, wide-angle shot of a diver hanging over a fan coral, for instance. This flexibility lets you work with a range of subjects on any given underwater photography dive - for example your dive might take you through a range of environments such as from a wreck, over coral and onto sand, all of which offer different subjects for which different lenses are needed. You can also react to chance encounters, such as an unexpected manta cruising over a critter site, quickly fitting your wide-angle to picture it or hitting poor visibility, in which case you might fit your close up lens and enjoy a really productive macro dive.

close focus wide angle

Close focus, wide-angle photography is a creative technique taught during your INON UK Level One Digital Underwater Photography Course. It relies on the combination of an extreme wide-angle lens and lots of depth of field. The INON UWL-H100 makes close focus, wide-angle underwater photography comparatively easy. Composition skills for close focus, wide-angle underwater photography are one of the topics of INON UK Learn with Lisa Days. These underwater photography improvement courses are classroom based, so you don’t even have to get wet to benefit.

Lens angles, fields of view and depth of field can be confusing. The introductory INON UK Level One Digital Underwater Photography Course explains these subjects in a straight forward and easily understood way. This and the INON UK Understanding Your Underwater Camera and Strobe Day can be useful programs to take before investing in underwater camera equipment as well as useful to more experienced underwater photographers. But the basics are that most compact cameras have a built in lens with a maximum field of view in air of 74 degrees. On land, this is a good compromise. There’s little distortion and it’s wide enough to take a group shot of three or four family members from, say, 1.5 metres away or for photographing landscapes. Given that on land compact cameras are often used as tourist cameras because of their small size and automatic point and shoot simplicity, and the daunting technical difficulties of making extreme wide-angle lenses that have little applications for casual snap shooting, this choice of built in lens makes sense. For more serious photography of more difficult subjects, such as a wildlife safari, a more sophisticated camera might be chosen. This is because the lens built into a compact camera usually has a limited range. For safari photography a telephoto lens, which magnifies like a telescope might be required. This is because our subject is likely to be a long way off in the distance. If we use our compact cameras built in lens it will look very small in our picture. For underwater photography the opposite is true. We need to be very close to our subject to take good pictures. As explained on the INON UK Level One Digital Underwater Photography Course, water absorbs colours, scatters and diffuses light and particles suspended in it progressively soften and obscure our view of our subject.

To overcome these effects and get a sharp underwater photograph with vibrant colours we need to get very close to our subject. Roughly within 25% of how far we can see when taking natural light pictures (so no more than seven or eight metres away if we’re lucky enough to have 30 metre visibility) and about one and a half to two metres away when using a strobe. Our built in camera lens can only shoot modest sized subjects at these distances – for example a head and shoulders portrait of a diver if we use a strobe. If we back away to get more of our subject in our picture, we’ll quickly lose colour, contrast and sharpness. Complicating our photography is the fact that our built in camera lens will lose about 25% of its field of view underwater. When we use a facemask with a flat window our field of view narrows and objects appear closer underwater due to refraction. Exactly the same thing happens to your camera lens. The INON UWL-H100 underwater wide-angle lens converts your built in camera lens or a compatible compact system camera interchangeable lens into an ultra wide-angle lens and overcomes many of the issues we’ve mentioned. It isn’t hyperbole to state that without a wide-angle lens many of the problems that cause disappointing underwater photographs are insurmountable.

Lens angle grid
Understanding the relationship between a lenses focal length, angle of view and how it behaves underwater is important. The INON UK Level One Underwater Photography Course explains the facts in a straightforward, easy to understand way. This chart, taken from the course, shows the different viewing angles of different lenses, with the 28mm frame indicating the field of view of most modern compact cameras. Limited visibility underwater means that backing off to include the whole picture with a 28mm lens will result in a soft focus image with poor colour. A fisheye or semi-fisheye lens is required to take a quality photograph, as used here by Mark koekemoer from The Underwater Camera Company. Mark co-designed the INON UK Level One Underwater Photography Course with INON UK's Steve Warren.

The INON UWL-H100 is an evolution of INON’s highly regarded and long established range of wet wide-angle lenses. INON’s long experience of designing premium quality underwater optics harks back twenty years to the ports for the first INON X2 SLR housings for Canon cameras. Canon lenses are among the finest in the world and INON’s X2 housing ports needed to maintain the highest possible image quality when these lenses were used underwater. Wide-angle lenses are tough to get the best out of underwater because of how water changes the way light behaves. Housing these lenses, obviously designed for optimum performance in air, required INON to design ports that correct these effects to as high a degree as possible for professional use underwater.

UWLH100 on PT050

The INON UWL-H100 wide-angle lens fitted to the Olympus XZ-2 in its underwater housing. The XZ-2 is one of the advanced compact cameras that features a large sensor, wide-angle lens and large maximum aperture. This combination of features inspired INON to design the UWL-H100 to take full advantage of these camera improvements. The Olympus XZ-2 is INON UK’s choice of school camera.

INON’s wet lenses are much more complex than a port for an SLR housing and combine a series of individual lenses, or elements, which precisely bend or refract light to create a wide-angle perspective. INON’s original wide-angle and fisheye wet lenses for compact cameras were groundbreaking and did much to make compact cameras useable for advanced underwater photography. Image quality proved high enough to enable Lisa and Steve to find willing publishers among glossy magazines including The Sea and Diver for photographs taken with low cost underwater compact cameras equipped with INON lenses.

front port flat 5

INON's wet lens system, shown here on the INON X2 housing for Panasonic Lumix compact system underwater cameras, allows great flexibility. The cameras own zoom lens is ideal for reef fish photography. It can be fitted with an INON UCL close up lens for macro photography. The INON UWL-H100 wide-angle lens is a good choice for shots of individual divers or manta rays. When equipped with the INON Dome Lens Unit 11, the increased field of view of the INON UWL-H100 converts the system for wrecks and low visibility photography. For specialist critter photography, the unique INON UFL-M150 ZM80 bug eye lens adapts the camera for extreme wide angle macro applications.

The INON UWL- H100 underwater wide-angle lens system was designed by INON to overcome problems that advances in camera technology had introduced. These advances were made to both the cameras sensors and the cameras built in lenses. Traditionally compact cameras had tiny sensors, roughly the size of a finger nail. By increasing the sensor size image quality could be improved, allowing greater enlargements or more radical cropping. The better performance of the sensor required lenses with better resolving power. Along with higher quality lenses, camera manufacturers began building in wider-angle lenses than before and one’s with wider or faster apertures or F stops for improved low light performance and greater depth of field control. Ideally wet lenses should exceed the image quality that the camera itself can produce. Otherwise the photographer can easily be frustrated by his or her results. Unlike most other wet lens manufacturers, whose lenses have not been upgraded since the move towards compacts with larger sensors and better built in lenses some years ago, INON decided to design an entirely new lens to meet new standards of compact and compact system camera performance. The INON UWL-H100 is the result.

PT054 double

Many underwater photographers prefer to light wide-angle pictures using dual strobes. Dual strobe lighting and many other lighting skills are taught on the INON UK Level Two Underwater Lighting Course. It's also important to properly trim your underwater camera. INON float arms help bring the camera back to near neutral buoyancy. A neutrally buoyant camera won't plunge into the depths if accidentally dropped and is easier to shoot one handed. It also makes composition easier as any instability increases the likelihood of misframing your subject. Composition skills for wide-angle photography are taught as one of the modules in INON UK's Learn with Lisa Days.

The INON UWL-H100 digital wide-angle lens is the hub of a system that includes mounts, dome ports and hoods. The lens itself features a durable aluminium body. It’s built to last. The lens elements are glass and are multi coated. The coating is needed to prevent reflections, which reduce the amount of light passing through the wet lens to the camera and which also cause ghosting and flare. Flare is a problem of wide-angle lenses in general and, underwater, scatter makes this much worse. It’s also sometimes introduced by poorly positioned strobes and video lights. Basic strobe positioning to ensure backscatter free, evenly lit pictures with a single strobe is among the practical skills taught during the INON UK Level One Digital Underwater Photography Course. More advanced strobe skills, including multi strobe use and creative lighting techniques, such as using snoots, is covered in the INON UK Level Two Underwater Lighting Course.

The INON UWL-H100 is available with three interchangeable camera housing mounts. The mounts are a specific length and their role is not just to attach the INON UWL- H100 to your underwater camera, but also to help ensure the best possible image quality. Often overlooked, possibly because most wet lens manufacturers don’t offer this level of perfection and don’t discuss it, the distance between the rear element of wet wide-angle lenses and the camera lens is critical to its optical performance. INON’s LD bayonet mount uses the INON LD Lens Base to set the correct optical distance. The LD Lens Base is used to mount the INON UWL-H100 and UCL close up lenses to specific underwater camera housings. Each INON LD Mount Base is specific to its designated housing and camera combination. INON are perfectionists about optical performance and if they do not offer an LD Lens Base for a camera and underwater housing you are considering, but one is offered by a third party, you may want to take advice from an INON UK dealer. A third party mount might not give satisfactory results. The LD lenses are fitted and removed with a fast quarter turn and feature a safety lock to prevent accidental loss of your valuable lens.

Video base

To ensure the best image quality, the cameras own lens and the positioning of any underwater wide-angle wet lens is critical. This fact is often overlooked. INON use special adapters, called Lens Bases or Lens Adapters to set the correct distance. The rear mount of the INON UWL-H100 is interchangeable. This mount is also used to align the UWL-H100 for the best performance. It also allows easy replacement of a worn mount or for the mount to be changed to fit a future camera system.

The M67 thread mounts allow you to use the INON UWL-H100 lens with many compact camera underwater housings from a range of manufacturers including Nauticam, Recsea and Ikelite as well as certain compact system camera housings, such as Olympus. The INON Type 1 and Type 2 M67 mounts set slightly different distances between the INON UWL-H100 wide-angle lens and the camera lens to allow for different port designs. M67 threads are taken from standard filter threads used on land cameras to attach lightweight filters and close up lenses. Ideally a more rugged, courser thread would be used for underwater camera systems, but it is what we’re stuck with. The INON mounts can be inexpensively replaced if they become worn as well as changed if you upgrade your underwater camera later on. This gives you the flexibility to keep using your INON UWL-H100 lens in the future and protect your investment. It is essential to check with your official INON UK dealer that your camera is compatible with the INON UWL-H100 wet lens. The fact it can physically attach to your housings M67 mount does not guarantee it or any other wet lenses optical compatibility with your camera.

The UWL-H100 wet wide-angle underwater lens is not provided with a lens hood when you purchase it. This is because INON don’t know if you will also be purchasing the INON Dome Lens Unit 11 at the same time. The INON Dome Lens Unit 11 is supplied with a dedicated hood. If you are not using the INON Dome Lens Unit 11 it is wise to invest in the INON Lens Hood. This not only helps to minimize flare, but also adds considerable protection for your INON UWL-H100 front element. Although INON UK can replace a damaged front element, prevention is better than cure.

dome 2 uwl-h100

When equipped with the INON Dome Lens Unit 11, the underwater field of view of the INON UWL-H100 is increased from 100 degrees to around 150. Depth of field is also expanded. This means your UWL-H100 wide-angle lens can economically be upgraded to a near fisheye lens in the future. The INON UWL-H100 combined with the INON Dome Lens Unit 11 is ideal for photographing shipwrecks, reefscapes, schooling fish and for working in low visibility.

Underwater photographers have different requirements to one another and their own needs may change over time as their interests and opportunities develop. For instance, for pool photography of babies and family groups, or open water pictures of individual mantas or basking sharks, the INON UWL-H100 lens may well be all you’ll ever need. But if you regularly work in poor visibility, photograph shipwrecks or need to portray schooling hammerheads or reef vistas, you’ll need to go much wider. The INON UWL-H100 is easily and economically upgradable to a near fisheye super wide-angle lens by adding the INON Dome Lens Unit 11. Increasing the field of view to as much as 150 degrees and further expanding depth of field, this is a lens in its own right. The dome element is glass and features multi coated surfaces, just like the INON UWL-H100 itself. The dome is mounted in a rugged aluminium mount and a lens hood is included. Assembly is required, which involves a few screws and two O rings. Many INON UK dealers will be happy to install your INON Dome Lens Unit 11 onto your INON UWL-H100 lens for you if you’d prefer.

The use of glass elements and aluminium to ensure the best quality optics and long lasting durability mean the INON UWL-H100 and INON Dome Lens Unit 11 will make most underwater camera systems front heavy. Using INON Float Arms to bring your camera system back towards neutral buoyancy and trim will make camera handling much easier. A neutrally buoyant and trimmed camera will not plunge into the depths if dropped, eliminates camera instability helping with accurate composition and is easy to shoot one handed. INON arms accept INON LD and INON M67 Lens Holders for safe and convenient storage of your INON wet lenses. You’ll also need to think about the number of arm sections and what lengths you’ll require to properly light stills pictures or video taken with your INON UWL-H100 wide-angle lens. Your decision needs to consider likely visibility, type of subject, distance to subject and whether you use a single underwater strobe or a pair. We don’t regard video lights as being as versatile as strobes for underwater stills photography for a variety of reasons, but they can be useful for close up work, as fill lights, for focus assist and for helping you see well enough at night to shoot wide-angle stills pictures. INON’s extensive selection of arms and adapters makes it easy to combine INON strobes and INON LE or INON LF video lights to suit your own preferences.

face lit

For people photography, the 100 degree angle of view of the INON UWL-H100 is often perfect. Wide-angle photography at night is sometimes overlooked, but can be very rewarding. This image formed part of a photo-story for a magazine. Most video lights lack the power needed for stills photography at night. An INON D-2000 strobe lit this picture. However, an INON video light, such as the LF2700W makes composing wide-angle photographs in the dark much easier as you can see all of the frame.

As we’ve explained it is very important to check with your INON UK official dealer that the INON UWL-H100 underwater digital wide-angle lens is compatible with your camera and housing. If it isn’t, INON may have an alternative wide-angle wet lens that is. The INON UWL- S100 ZM80, for example, is INON’s welcome solution to popular compact cameras, including some superzoom models and several Canon Powershots, that are not really compatible with conventional underwater wide-angle lenses.


Not all cameras can accept the INON UWL-H100 wide-angle lens because of the design of their built in lens. The INON UWL-S100 ZM80 was developed to work with some of these cameras. It is extremely important to confirm with INON UK or an INON Uk official dealer that the underwater camera system you are considering buying is compatible with the wide-angle lens you want. Although wide -angle lenses can often be physically attached to an underwater camera, that does not mean they will work!

You can help protect your INON UWL-H100 lens by using the proper lens caps. Lens caps have a knack of going missing, so it’s wise to get a spare set when you buy your lens. The most likely place to lose your caps is on a trip, leaving your lens very vulnerable to being damaged. Not only can repairing or replacing your lens be expensive, it may mean it cannot be used for the remaining days of your holiday. INON also provide neoprene soft pouches to carry and store your lenses in, which provide some shock protection as well.

Your INON wide-angle lens, when purchased through the INON UK shop or an official INON UK dealer, includes some valuable benefits. These include a three year extended warranty and significant discounts on many INON UK underwater photography continuing education courses and events. Not all INON products sold in UK are supplied by INON UK and do not carry INON UK exclusive benefits – some are grey or parallel imports. Check our official INON UK dealer list to be sure you get full product support.

Five Features and Benefits of INON UWL-H100 Digital Wide- Angle Wet Lens

Works in Air and Underwater.

The INON UWL-H100 wide-angle lens works as a fisheye in air. This can produce some very dramatic forced perspective results as well as curved horizons, and can be very useful for working in tight spaces.

Upgradable to Semi- Fisheye.

Adding the INON Dome Lens Unit 11 lets you easily and economically upgrade your INON UWL-H100 super wide-angle lens to a semi –fisheye. This is needed for really productive wreck and reef panoramas, is ideal for photographing big shoals of schooling fish and an essential tool for working in low visibility.

Your Entry to Close Focus Creative Underwater Photography.

The INON UWL-H100’s superb near focusing ability and great depth of field makes taking classic close focus, wide-angle forced perspective images really easy. Small size of INON UWL-H100 front element helps with shooting wide angle macro pictures.

Forward Compatible.

Three different camera housing mounts and high quality optics designed for larger sensor cameras mean your INON UWL-H100 wet wide-angle lens offers considerable forward compatibility if you change your underwater camera in the future.

INON UK Benefits Package.

INON UWL-H100 benefits package includes extended warranty and big discounts on INON UK underwater photography continuing education courses with Lisa and Steve.

V4 dome lens unit

The INON UWL-H100 wide-angle lens is an excellent choice for shooting underwater video. Along with using the INON UWL-H100 lenses and INON lighting systems on conventional camcorders, INON also produce lenses specifically for Go Pro cameras.