I would like to take a picture with a red filter. Can I use it in any depth or do I need more than one? Are there any differences in the filters?
Answer by PanOceanPhoto
Filter photography is a complex subject area. It is most often used to “return” the red portion of the light underwater, which it loses in depth. Theoretically, you would need a special red filter for each depth, because the red portion that the water “filters”out of the white light changes continuously.
In practice, however, this is done in a different way: from approx. 5 metres (in clear blue water) a filter is used. And then – very importantly – you have to work on the white balance. When your camera writes RAW files, you do this later on your computer – if it records JEPG files in the camera before you press the record button. To find out how to do this, please refer to the operating instructions of your camera. Auto white balance will no longer work in 99% of cases.
When you do the white balance in the water, remember to do it whenever you change your depth. This is because with increasing distance, the red portion of ambient light decreases with increasing distance that light travels through the water.
Nevertheless, it can be useful to use different filters. Because first of all, red is not always red. You can see that with the naked eye. But more importantly, blue is not just blue. The colouring of the water varies greatly in the world’s oceans. This is due to the different concentrations and types of phytoplankton and dissolved minerals. And it is possible to change and adjust the white balance at a later date.
However, there are limits to the degree of change. So if you notice that your image quality is degraded when you make the white balance, you should look for a suitable filter and use it. The quality of your camera sensor is very important. The better this is, the greater the tolerance for adjusting the color temperature.