Underwater filming and photography with an actioncam

With an action cam, you can film and take photos underwater, in addition to the typical applications, such as video recording or photos during sports activities. How well this works ultimately depends on the particular equipment of the actioncam. In cameras in the higher price segment, for example, very high-quality, fast optical components are installed. This becomes important when you want to dive deeper and then have to use filters.

If you only want to take videos or photos, e.g. of snorkelling up to 3m water depth, you can already get usable results with cheaper actioncams.

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Waterproof action cams or waterproof housing?

If an action camera is already waterproof “out of the box”, this has several advantages. For one thing, of course, the camera is protected and you don’t need an extra case. For example, without an additional housing, all GoPro Hero7* cameras are waterproof to 10m.

The disadvantage is that without an additional housing the diving depth is limited to approx. 10m. So if you want to dive deeper, you can’t get around a waterproof case.

Do I need a color filter if I want to film or photograph underwater?

Whether you need a color filter depends on how deep you want to dive and whether you want to do it in fresh or salt water.

If you only want to go up to max. 5m deep diving or snorkeling, you do not need an additional color filter. Up to a depth of 15m you should use a color filter. A red filter for salt water or a magenta filter for fresh water.

To understand why you use a red or magenta filter, you have to look at the physics behind it. The visible light has a wave character in the range of 380nm – 750nm (nm = nanometer). The smaller the wavelength, the higher the energy of this light component. Violet light lies with approx. 380nm in the energy-richest range of the visible light spectrum. The red light, on the other hand, is in the range of about 750nm and therefore has less energy. Wavelengths above 750nm are in the range of thermal radiation. At wavelengths shorter than 380nm, the light passes into the high-energy ultraviolet range. By the way, X-rays already start at 10nm.

So why do you take a red filter if you want to dive deeper?

It’s honestly not that easy to understand. To do this, the first thing you need to understand is how the image generation takes place in the camera.

Each electronically generated image is created from three colors per pixel. These are red, green and blue. From the mixture and the saturation of these the basic colors can be indicated on the screen with 8Bit color depth up to 16.8 million colors. This is also called additive color mixing.

The image sensor in the Actioncam and any other digital camera also captures three color values per pixel in varying saturation and brightness, which make up an image.

Now we come back to the red filter*. From a water depth of 5m the red part of the light in the water decreases and photos and videos become rather greenish bluish. This is simply due to the fact that water is much denser than air and with increasing depth, the lower-energy red light component is virtually swallowed by the water. Now you cannot add “red” with the red filter but the red filter or magenta filter is the respective complementary color filter to blue or green and reduces this color portion in the image. (in the picture above the complementary colors are opposite to the respective primary colors) This way you get a color-correct image again.

However, using a color filter also reduces the amount of incident light by 1 – 1.5 f-stops. Therefore, this will not work really well with all action cameras. Here, the higher-priced action cams with better optics clearly have advantages.

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Artificial lighting from 15m

If you want to film underwater and dive deeper than 15m, you won’t get any further with a color filter. Here the light intensity decreases further and even a good action camera reaches its limits with the optics. At the latest here you need additional lighting. With the additional lighting one has in deeper water then also no more problems with falsified colors.

There are several ways you can use supplemental lighting. Combinations of lamps and actioncam holders are recommended. With this, the camera can then also be guided well.

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In addition to additional lamps, there are also combinations of lamps with a housing. The housing in which you put the action camera is waterproof and thus suitable for greater depths. With such a combination you have a very compact device that you can easily operate with one hand. For an actioncam a really useful accessory.

Summary

The topic or the connections are admittedly not that easy to understand. As a rule of thumb, however, you can say the following:

• up to 5m water depth – no additional colour filter
• from 5m – 15m water depth – red or magenta filter
• from 15m water depth – additional lighting

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Letzte Aktualisierung am 2024-12-21 / Affiliate Links / Bilder von der Amazon Product Advertising API