Why I Stopped Using Red Filters (And What I Use Instead)

My first phone housing came with a red filter. I won't name the brand, but the seller promised natural colours underwater. Easy. Except in the Seychelles, the water isn't always that postcard-perfect crystal blue. It's often turbid, green, loaded with particles. And in those conditions, my red filter corrected nothing at all. The colours were flat, dull, never true to what I saw with my own eyes.

I persisted. Dozens of dives with that filter, and every time the same verdict: the result was never what I hoped for. Too dark at depth, too pink near the surface, and in the green waters of the Seychelles, a muddy mess of tones that looked like nothing.

But the real problem showed up a few weeks later. A scratch. Just one, on the filter. Not huge, not visible to the naked eye on the surface. Except underwater, my phone's autofocus locked onto that scratch. Every single photo came out blurry. Every one. And the worst part is that it took me a full week to figure out where the problem was coming from. An entire week wondering why none of my images were sharp, checking my settings, doubting my gear. When the culprit was that scratched piece of plastic in front of the lens.

That filter became unusable. Not just for colour correction, but for taking photos at all. One scratch, and it was over.

That's when I understood: red filters don't solve the problem. They create new ones. And sometimes, they cost you entire weeks without you knowing why.

Today, in my training programme, I ban them. And I'm going to explain exactly why.

Water absorbs light selectively. Reds disappear first, from just 3 to 5 metres down. Then oranges. Then yellows. At 15 metres, only blue-green remains.

This is pure physics. Neither your GoPro nor your 4,000-euro DSLR can change any of it. The only question is: how do we compensate?

The industry's answer is the red filter. My answer, after years in the field in the Seychelles and beyond, is anything but that.

They're sold to you as a miracle fix. A coloured piece of plastic in front of the lens and presto, natural colours. If it were that simple, I wouldn't be teaching anyone colour correction.

Here's what the industry doesn't tell you.

They darken the image. A red filter physically blocks part of the light entering your camera. Underwater, where light is already the scarcest resource, you're sacrificing precious information. The deeper you go, the darker the filter makes things. At 15 metres, you get an image that's dark AND still blue.

They don't adapt. A filter is calibrated for one depth and one type of water. You descend from 5 to 12 metres during your dive? The filter stays the same. At 5 metres it overcorrects (everything turns pink), at 12 metres it undercorrects (everything stays blue). You spend your dive with a tool that's only accurate for a fraction of the time.

They still require editing. Here's the irony: you buy a filter to avoid post-production, and you end up in Lightroom anyway, correcting the pink cast or the overly dark image. The filter hasn't simplified anything, it's just added a step.

They scratch, and they destroy your autofocus. This is the most insidious trap, the one that personally cost me an entire week of unusable photos. In real conditions, the filter picks up scratches. And when the autofocus detects that scratch, it focuses on it instead of your subject. Result: every photo is blurry, and you don't understand why. You check your settings, you doubt your camera, you waste enormous amounts of time. When the problem is just a scratched piece of plastic in front of your lens.

They throw away information you'll never get back. This is the fundamental point. A filter physically blocks wavelengths. Once blocked, they vanish from the file. Permanently. In post-production, you work with the full signal captured by the sensor. The difference is irreversible.

At AquaExposure, we correct colours with a 4-step method, in this order of priority. No gadgets, no shortcuts. Just method.

Step 1: Choose the Right Time and the Right Angle

Colour correction starts before you even touch your camera. Between 10am and 2pm, the sun penetrates the water more directly. Position yourself with the sun behind you or at its zenith. You naturally recover more of the light spectrum. It's free, it's reliable, and it radically changes your images.

Step 2: Set Your White Balance Manually

This is the most underrated skill in underwater photography. Auto white balance (AWB) is unstable underwater: it oscillates between cold casts and random corrections from one image to the next.

My recommendation: lock your white balance at 5000K. It's a reliable starting point for the vast majority of situations. If you have the experience, switch to manual/custom white balance for an even more precise result, but 5000K is your safety net.

Step 3: Get Closer to Your Subject

At 3 metres distance, the water between you and your subject absorbs a huge amount of colour. At 50-80 cm, absorption is minimal. That's why the best underwater photos are taken up close. You don't need a massive zoom: get physically closer (always respecting the animal's comfort zone, minimum 2 metres for living subjects).

For non-living subjects (corals, wrecks, reef landscapes), get down to 50-80 cm. The colour difference is spectacular, and you haven't bought a single extra piece of gear.

Step 4: Post-Production, Gentle and Targeted

This is the last link in the chain. Not the first. If you've done steps 1 through 3 well, your post-production will be light and fast.

The practical workflow: - Shoot in a Flat or LOG profile (Protune Flat on GoPro, D-Log M on DJI, I-Log on Insta360) to capture the maximum dynamic range - Yes, the raw image will look "grey" and "ugly" on your camera screen. That's normal. The beauty is hidden in that grey file, because it contains far more usable information than an image already processed by the camera - Correct in DaVinci Resolve (free and excellent), Lightroom, or Snapseed on mobile if you're just starting out - Apply an underwater LUT if needed

Quick aside, because this topic comes up all the time.

DJI Osmo Action 5 Pro: the "Underwater" mode uses a dedicated colour temperature sensor that adjusts white balance automatically in the firmware, before encoding. It's a specialised hardware auto-WB, not artificial intelligence. It works in Normal mode, but in D-Log M, this processing is disabled.

Insta360 AquaVision 3.0: marketed as AI, it's actually a hybrid pipeline. A scene detection system determines the parameters, then a conventional algorithm adjusts the R/G/B channels. This happens in post-processing within the app, not in real time.

These automatic corrections are handy for quick content to share. But for careful work, nothing replaces manual correction on a calibrated screen. And above all, they confirm the direction: the processing happens after capture, not with a piece of plastic in front of the lens.

I'll be direct: for me, a red filter serves only one purpose. Physically protecting the lens of your camera during the dive. Full stop.

It's a coloured lens protector. If you want to shield your lens from impacts, particles and sand, a filter does the job. But don't ask it to correct your colours. That's not what it's for.

Forget filters for colour correction. Instead, learn the 4 steps in order: timing, white balance, distance, post-production.

It's more work at first, yes. But that's where you truly learn to understand light underwater. And once you master this chain, you'll achieve results that no filter could ever match, regardless of brand or price.

What matters is understanding why light behaves the way it does underwater, and working with it instead of sticking a coloured bandage on your lens.

This debate goes far beyond technique. It touches on something more fundamental: why you go underwater with a camera, and what you truly want to bring back to the surface.

Let's start by being honest. Underwater flash is not an aberration. There are serious professional photographers who use it with rigour, with discernment, and who produce exceptional images. This isn't a question of right or wrong. It's a question of philosophy, context, and honesty about the consequences.

Flash as a Tool of Control

The main argument for flash is total control over light. You no longer depend on weather, time of day, or depth. You bring your own light source and control everything. For a scientific photographer documenting a specific species at 25 metres inside a cave, that's a solid argument.

The problem is that control comes at a cost. And that cost isn't only technical.

The Brutal Interrogation

Imagine an animal that has been moving through its territory for hours. It's relaxed, busy, unaware of your presence. And then you find yourself 1.5 metres away with a light burst of several thousand lux for 1/200th of a second. For eyes adapted to the relative darkness of the water, it's a sensory assault without precedent.

The AquaExposure Doctrine names this situation bluntly: a brutal interrogation for the animal. Not out of malice on your part. Out of ignorance of the real consequences of what you're imposing on it.

Behavioural studies show that flight reflexes triggered by intense flash can persist for several minutes. In that state, the animal no longer behaves naturally. What you're photographing is a stressed animal. It's not the subject you thought you were capturing.

The Three Circles and Why Flash Destroys All of Them

Every wild animal lives within three invisible, overlapping spaces around it.

The first is the alert circle: the animal has spotted you, it watches you, but it continues its activities. You exist in its world without truly disturbing it. This is where the best photos are born.

The second is the tolerance circle: the animal maintains a minimum distance from you. It accepts your presence as long as you respect this implicit boundary. A sudden movement or unexpected sound can push it back towards this comfort zone.

The third is the flight circle: you're too close, or you've done something invasive. The animal disengages. It leaves, or freezes in a defensive posture.

A flash fired within 2 metres of an animal sends it straight from the first circle to the third, with no transition. The animal didn't have time to assess you, to get used to you, to decide you're not a threat. You've taken that decision away from it.

Natural light, on the other hand, keeps you in the first circle for minutes on end if you move slowly and breathe calmly. It's that duration that produces authentic images.

The Legitimate Exceptions

At AquaExposure, we don't preach absolutes. There are situations where artificial light is the only reasonable option, and it would be dishonest to deny them.

Night diving is the most obvious. In total darkness, without a light source, no image is possible. A dive torch or dive light aimed with care, without pointing directly at the animal's eyes, remains acceptable.

Deep macro on non-mobile subjects (a nudibranch on a rocky substrate at 20 metres in an area with no direct sunlight) can

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