Red filter vs editing

A red filter puts color back before the light reaches the sensor, which works well in blue water with sunlight at moderate depth. Editing fixes color afterwards and works at any depth, but can only recover red that the camera actually recorded. Most divers get the best results by knowing when to use each.

What a filter does

A red filter blocks some of the blue and green light so the remaining red counts for more. Because it removes light rather than adding it, the camera has to compensate with a higher ISO or a slower shutter, which can add noise or blur in dim water.

• Red filters are for blue, clear water.
• Magenta filters are for green water, where the cast comes from plankton and dissolved matter.
• Some brands sell stronger "deep" versions for further down. Check the depth range the maker gives.

What editing does

Color correction after the dive rebalances the channels: it lifts red, pulls back blue or green and stretches contrast. It works on every photo and clip, at any depth, and you can always go back to the original. The limit is information: if the red channel is almost empty, boosting it brings up noise rather than color.

Side by side

What we recommend

1. Blue water, 5 to 15 m, sunny: use a red filter, then a light touch of correction to finish.
2. Green water: use a magenta filter, or none and correct afterwards.
3. Shallow snorkeling, deep dives, changing depths, lights on: no filter, correct afterwards.
4. Not sure? Shoot without a filter. You can always fix color later, but you can't remove a filter's cast from a clip that is already red.

If you use a filter, keep the correction gentle. In VividSea, lower the Auto slider to around 40 to 60% on filtered shots so they don't turn too warm. You can test how much a photo needs with the free browser tool.

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Common questions

At what depth does a red filter work?

As a common rule of thumb, a red filter works in blue water with sunlight from roughly 5 m to about 15 m. Shallower it can turn the image too red; deeper there is too little red light left for it to balance.

Should I use a red filter with a video light?

No. Lights put red back into the scene, so a red filter on top makes everything red or purple. Take the filter off when you use lights or strobes.

Is editing better than a filter?

Editing is more flexible because it can be adjusted or undone, but it cannot recover red the camera never recorded. A filter at the right depth plus a light correction afterwards usually gives the cleanest result.

Sources

• Depth ranges are widely used dive photography rules of thumb for clear water, not precise measurements. Filter makers publish their own ranges.
• NOAA National Ocean Service, Why is the ocean blue?

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