There’s a broad range of wide angle wet lenses available for underwater photography from brands such Nauticam, Weefine, Fantasea and Backscatter. But the one I’ve been recommending most often to people since it came on the market is INON’s UWL-95 S and in particular their XD bayonet mount version. In this article I’m going to explain why in my view it’s one of the best options on the market.

If you aren’t aware of what a wide angle wet lens is, it’s a lens that fits onto the port of an underwater housing to increase the angle of view beyond what the camera lens on its own gives. That extra angle of view allows you to be closer to your subject and still frame the same scene, which in turn helps give sharper, more colourful, better lit pictures and with less backscatter when using flash or video lights.

The UWL-95S is sold as a flat fronted lens which gives a fairly modest maximum angle of view of 95º but you can add a dome unit sold as a separate part which increases that to a maximum of approximately 141º. That angle of view is one of the highest available from a wet lens with top priced lenses such as Nauticam’s WWL-C and WWL-1B and Fantasia’s UWL-09F and UWL09Pro giving 130º. You can get somewhat wider with lenses such as Weefine’s WFL01 (145º) and WFL02 (150º) but they don’t have the UWL-95’s other advantages.

Wide angle wet lenses are all designed to give the greatest angle of view when your camera lens is at a specific full frame equivalent focal length. This is what the focal length of your camera would be if you were using a full frame sensor camera and is calculated by multiplying the actual focal length of the camera lens by the crop factor of your cameras sensor. For example the crop factor of a Micro Four Thirds sensor camera such as the OM System OM-1 is two. Luckily in the case of compact cameras manufacturers and reviewers give equivalent focal lengths in the camera specs. For example the OM Systems TG7 has a zoom lens which goes from 25mm to 100mm equivalent focal length. The two commonest equivalent focal lengths that wide angle wet lenses are made for are 24mm and 28mm.

The UWL-95S gives its widest angle when used with an equivalent focal length of 24mm which makes it ideal for use with the Sony RX100 cameras which have lenses that go that wide. It’s also a great match for the Olympus/OM System TG’s which go as wide as 25mm. It still gives plenty of angle of view at 28mm and I use it with the Canon G9X MkII camera in a Fantasea housing. Giving its widest angle at 24mm does mean that if you have a suitable port on your housing and a lens that doesn’t go any wider than 24mm you shouldn’t get any vignetting in your pictures. Those are the dark corners or edges that occur in pictures which you either have to zoom the lens in or crop out with editing software to get rid of.

One of the biggest advantages of this lens is the dome being a separate part. Most wide angle wet lenses have the dome fixed to them. That means if you do scratch the dome and you can’t get the scratch polished out you either have to return the lens to the manufacturer to replace the dome or have to replace the entire lens. The INON lens has the choice of two different Dome Lens Units. One is acrylic and has an RRP of £144, the other is glass and sells for £279. Acrylic domes are softer so scratch more easily, but it is also easier to polish scratches out of the using plastic polishing kits such as Novus. Glass is more scratch resistant but harder to remove scratches once they have happened. The fixed domes on most wide angle wet lenses are made from coated polycarbonate and while the coatings are there to help resist scratching once a scratch occurs they make it extremely difficult to remove the scratch and in my experience attempts to do so usually make matters worse.

There is another slightly more niche advantage to having lens without a fixed dome. The UWL-95S can be used on dry land without its dome as a fisheye conversion lens giving an angle of view up to 159º. To use it in this way you will need to have your camera in its underwater housing.

Another big thing in the UWL-95’s favour is the choice of mounts available for it and in particular INON’s XD quick change bayonet system. You can buy the lens with either a 52mm, 67mm or XD bayonet mount. But you aren’t permanently tied to those as each lens fitting can be bought as a part and the original one removed and replaced. Of the mount options the XD is the one I recommend to most people. The lens itself is cheaper with this mount at £407 compared to £425 for the two screw threaded versions. But you will need to buy the bayonet mount to fit on the lens port of your housing. There’s a choice of three different mounts, an M67 for some flat housing ports (read on for more about this), one specifically to fit the Olympus PT-056/058/059 housings for TG cameras and one for the Sony branded URX100A housing. All three mounts are £34 each.

INON also do a range of lens holders for 52mm, 67mm and the XD mount lenses. These include ones to fit lattice style strobe arms, INON’s more exotic arms and the accessory/cold shoe on underwater housings. The version of these holders for the XD system are considerably cheaper than screw thread versions. An XD holder for a strobe arm cost £19 while a 52mm one costs £35 for example. The XD mounts and holders are also a great deal cheaper than the versions by other brands such as Nauticam or Fantasea. But bear in mind that while in most cases macro wet lenses will work fine with different bayonet mounts wide angle lenses give best results with a system that has been designed specifically for them and in some cases such as the Nauticam lenses you are tied to using their system because it is built into the lens.

A bayonet system makes it much quicker and easier to remove and replace a wet lens during a dive This makes things less fiddly when you ‘burp’ the lens by letting air out from between the lens and the port after getting in the water. But where it really helps is when you want to photograph a broad range subjects from wide angle to quite small ‘macro’ subjects in the same dive when combined with a compact camera or a mirrorless camera fitting with a short zoom ‘kit' lens. With the TG cameras which have very close focusing modes you only have to take the wide angle lens off to switch to macro where as with the compacts and mirrorless cameras the XD system helps even more by allowing you change from the wide angle wet lens over to macro wet lenses with the same bayonet mount.

As well as the general quick change advantage that any bayonet mount gives I find the XD system is least expensive, most compact and lightweight of the various offerings on the market. It’s also quite simple to use and fit. But we have discovered however that it isn’t compatible with quite a few housing ports including on the Fantasea housing for the Canon G7X, G7X II and G7X III and Isotta M67 flat ports. Sadly the depth of the 67mm thread on the ports of those housings for all three models of camera are too shallow and use of the system can result in damage to both housing port and the lens fitting. In addition while initially there wasn't an issue using the mount with the flat M67 port on our Nauticam housings after some use the fitting became stiffer and the back of the lens appeared to be pressing against the glass of this port. So far we haven’t found this issue with the Fantasea housings for the Canon G9X and G9X II and the Sony RX100’s but those housings are a different design with port glass that does not got right up to the threads. Because of this Inon currently aren’t recommending the use of the UWL-95S XD with their XD mount for M67 ports, only their macro XD lenses. Instead you’ll have stick with a screw thread but if the issue is fixed you could then change over to XD mount later by changing the lens fitting.

There is also another flaw with the XD mounts for 67mm threaded housings. That is to do with the small screw in pegs that come with the mount and are designed to stop the mount rotating by fitting in the notches that most housing ports have on them. Unfortunately ports vary in external diameter and that means in many cases these anti-rotation posts don’t work. But this isn’t a big you can tighten the fitting enough that it won’t rotate during use without you applying quite a lot of force and if it does and you start seeing the hood of the dome in your pictures you can rotate it back into place during the dive. This isn’t an issue with the mount for Olympus TG housings because it has a cutout that fits against the flash diffuser and prevents it from rotating.

Inon are aware of these problems and along with their distributor in the UK we’ve been trying to come up with solutions to both problems. in my view this is a great system that with a few tweaks would be usable with most M67 housing ports.

Optically the UWL-95S gives sharp results, does not seem to lose sharpness when you zoom through and allows focusing right up to the dome. That last feature is to something to be aware of because you can get so close to a subject that you risk scratching the dome and/or damaging your subject.

It’s low overall cost when bought as a system with dome, bayonet mount and a lens holder compared to its competitors that don’t have the option of acrylic or glass domes that can be changed by the user makes it currently the best value wide angle wet lens on the market.

Thanks as always for reading this. do get in touch if you feel I’ve missed something or have any questions. We can supply INON, Nauticam, Weefine and Fantasea equipment . All prices in this article include UK VAT and were correct at time of writing. To order equipment, get quotes etc contact us by emailing info@alphamarinephoto.com

If you’d like to learn more about underwater photography we run courses online and workshops in the UK and overseas. Email us with any enquiries or use our contact form to get in touch and sign up to our newsletter.

We also run a Q and A group on Facebook which anyone is welcome to join if they obey the rules.

If you found this article useful, but are not planning to buy equipment from us or do a workshop you can give us your support though our ‘buy me a coffee’ page. Be aware links to Amazon or Wex listings are affiliate links and we get a small percentage if you buy something through them.