Hey everyone,

A lot of people who don’t shoot underwater very often think the same thing: “I already have a versatile 24-70mm or 24-105mm standard zoom lens-why not just use it underwater too? I’ve done a bit of research on underwater photography and know I should use it with a dome port so I don't lose my wide field of view.” (These are currently among the most popular standard zoom lenses on the market, which is why we’re using them as the main examples in this post.) Unfortunately, this is one of the most common misconceptions in underwater photography.

Important clarification: This discussion applies specifically to underwater and split-shot photography using your Salted Line underwater camera housing. It does not apply to surface, surf, or wave photography.

However, if you use the 24-70mm or 24-105mm standard zoom lenses for surf photography or shooting in the waves, Flat ports are the way to go. They work perfectly in these conditions without any issues.

And now let’s break it down simply and clearly.

A wide-angle lens captures a really broad scene even when you’re very close to your subject. A standard zoom lens like the 24-70mm or 24-105mm is the classic “all-in-one” option. You twist the zoom ring and the view gets wider or tighter. It feels convenient on the surface, in surf and wave environments, but underwater the situation changes completely.

Underwater, to get good quality photos, you will generally need to use a dome port. To preserve the true angle of view of your lens for underwater photography, a dome port is essential.

Let’s quickly go over what a dome port is. The dome port is a semi-hemisphere made from glass or optical acrylic on the front of your Salted Line waterproof camera housing. Its job is to correct the way light bends when it travels from water into air. When using a flat port for underwater photography instead, you lose approximately 28% of the lens’s angle of view. In addition, edges become soft, colors fade, and you often see distortion and darkening in the corners. We’d like to remind you once again that this does not apply to surface, surf, or wave photography.

Here’s where the problem appears with 24-70mm and 24-105mm zooms: when you change focal length, the lens physically extends forward like a small telescope. This movement shifts the entrance pupil (the critical point inside the lens) away from the best lens position in the dome. For a dome port to perform at its best, that pupil must stay in the best position at all times. That said, there are some exceptions for fisheye and ultra-wide lenses.

As soon as the pupil moves from the best position, you start getting soft corners, color fringing, unwanted distortion, and focus difficulties at the longer end of the zoom. The result is that these zooms are noticeably worse than wide-angle options.

If you already own a 24-70mm or 24-105mm standard zoom lens and have decided to use it underwater anyway, here’s what you need to know. You can use it at 24mm or with only very slight zooming. In most cases it performs acceptably in the 25-35mm range. Anything beyond that and you’ll start running into focus issues or noticeably soft corners. The further you zoom, the worse the results become. Even if the lens physically fits inside your Salted Line underwater camera housing bundled with a dome port and there is enough space, it doesn’t mean it will perform optimally with a dome port. That said, you can still use it, mostly from 25 to 35 millimeters, with limitations, and we offer compatible Dome ports and Zoom gears to help you get the most out of your existing lens. This is fair for the majority of standard zoom lenses.

Please note: That you can check our Ports Compatibility Chart, which clearly indicates exactly which port each specific lens is compatible with.

Bottom line: 24-70mm and 24-105mm are fantastic lenses for surface, surfing and wave photography when using a flat port, but they are simply not ideal for dome port underwater shooting. Choosing the right wide-angle lens from the start gives you much better images on every dive. It’s one of those small decisions that makes a huge difference once you’re underwater.

Please keep in mind that the information above applies specifically to still photography. For professional videographers, everything is quite different. Many pro underwater videographers do successfully use 24-70mm and 24-105mm standard zoom lenses with Long flat ports underwater-especially when shooting hybrid content (a mix of close-up, medium-range, diver portraits, and dynamic action shots). However, for true wide underwater video featuring large reefs, expansive seascapes, and big scenes, the majority of professionals still prefer dome ports paired with wider lenses such as 16-35mm or fisheye.

Have questions about choosing the right lens or dome/flat port for your Salted Line waterproof camera housing? Feel free to email us at support@saltedline.com or message us on social media. We’re always happy to help.

Stay safe, stay dry, and happy shooting!

- The Salted Line Team

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