The underwater world has captivated the human being forever. The photographers of nature, have in this photographic discipline an ally to get different shots. While this type of photography would give to write a monograph, I will try to give you a brief introduction to the technique that surrounds this type of photography.
In this case, I will make specific mention of the type of photography that takes place at a certain depth, since it is the one in which we will find more singularities. We speak of depths that need access with a bottle. But many of these ideas apply to snorkeling, or to a simple pool.
What is needed for underwater photography ?
Underwater photography is still a minority field, and there are two obvious reasons. The first is the difficulty inherent in a practice of risk such as diving, although it is often said that it is the safest sport that exists. The second is the material, because the accessories we need to submerge in the water can cost us more money than our photographic equipment.
On the first difficulty I can hardly say, except that I recommend encouraging you to try out this fascinating world, getting before the corresponding license (previous course and exam). The most widely known recreational dive license in the world is the PADI Open Water Diver (Professional Association of Diving Instructors). Most diving schools are approved to teach these courses. Even among the specialties that exist within the PADI courses; There is one specific for underwater photography.
Once you have the license, you will not have another to practice and practice, because loading photographic equipment in the depth will introduce a point of difficulty in the task of diving. At the very least, I recommend you do some immersion test with the equipment before you take it seriously to get accustomed to it. you may need scuba diving regulator.
In general, and unless you have high levels of demand, it is usually best to use high-end compact cameras. The proliferation of the EVIL, have brought a breath of fresh air to this discipline through increasingly compact cameras but with greater noise control. But beware, if you want to take full advantage of photography (especially wildlife in motion), you must ensure that you have a continuous AF option.
It is also important that you bring a coupled flash (I'll explain why). It is desirable that it has an acceptable focal range for all kinds of situations. For example, a 28-100mm with possibility to shoot in macro would be ideal.
SLR cameras are used for very advanced underwater photography, and before asking you to ask this question: what happens if I cross a whale shark and I have come down with a macro optics mounted? The answer is: little thing. When one goes down with one of these cameras it does it with a very concrete objective. Below we can not change optics, unless we have a very expensive and advanced equipment.
The waterproof case.
The choice of the waterproof case must be made when buying the camera, as there are no boxes for all models. There are two varieties: metallic, more resistant, complete and oriented to the professional environment and polycarbonate, more bulky, cheaper and available for more camera models.
Obviously, when acquiring it will have to evaluate that it supports the functions for which we are going to use them, for example: do you have TTL connections for flash? To what depth is guaranteed? Will we have to give up some command from our camera?
Maintenance will also be required. Any minimum water leakage could spoil our equipment, especially at depths to which pressure would accelerate the flooding of the watertight compartment. Before and after each dive, the joints must be thoroughly cleaned and lubricated. And never have to open it while it is wet: better wait to get home.
In general, the more we can do without the flash to take a photo and take advantage of natural light, the better, because the water has particles in suspension, and these are reflected in the photograph giving us unwanted effects. But the reality is that from a certain depth, the flash will need it in 99% of cases.
As I said before, it is desirable that the camera has a built-in flash. The reason is that in general the external flash units are usually connected to the underwater cameras through fiber optic cables that trigger enclave cells. We can put some duct tape on the flash of the camera so that its front light does not intercede in the scene.
As for models, we must purchase special units for underwater photography. Again, it will be up to us to develop a good amount of money. It is also possible to purchase watertight cases for flashes that we use on the surface. We will not have the versatility or ergonomics of an underwater flash, but it may be a more economical solution.
Before starting to use it is important to know for the Guide Number (NG) of our flash for use in water. Manufacturers rarely give us the number in water, but if they do, they are usually unrealistic. If you subtract 3 or 4 units, it will be something closer to reality. A good practice is to make a diaphragm / distances / power table and then confirm them with the experience. Each flash behaves differently. This information will give you valuable information: how far do you have to put it to expose an object correctly combining its handling with the diaphragm of our camera.
They consist of strips with handles to which the casing and articulated arm of the flash are screwed. In this way, we will carry the whole set with the comfort of being able to hold everything with our hands. Little to be said except that this accessory is a plus amount of money in the final investment.
Decrease in natural daylight.
The possibility of photographing and visualizing objects on the seabed is due to sunlight propagating from the surface. However, we must know that in propagating by a different medium, its properties are also different. Two processes influence:
- 1. The physical properties of light: reflection on the surface, refraction (the change of direction of light upon entering a medium of different density) and extinction (in more depth, less light).
- 2. Physic-chemical properties of water: water transparency, suspended particles, the ability to absorb radiation, and so on.
Obviously, we cannot analyze the water every time we do a dive, so our experience will give us the information of the intensity of light in each depth. In technical books on this subject you will also find tables of generic equivalence between the depth and difference of EVs.
Another phenomenon characteristic of the immersion in the sea is that the absorption of the light is causing changes in the colors that we visualize. Thus, from 3 meters the red becomes brown, the oranges and yellow disappear and from 15 meters everything is blue. Using external flashes we can avoid this loss of color and capture all the chromaticity of the seabed.
Here is a set of tips to keep in mind when photographing while diving.
Look around: when diving, the trend tends to be to look down, since the diving is performed in a horizontal position. It is not too much to look around, to look for different frames.
It uses short-range lenses: they are the ones that are used most of the time, and at long distances there is no visibility. The ideal is to have macros (a type of photography very grateful in this environment) and angular.
Get as close as possible: water has many particles in suspension, and light does not propagate as well as on the surface. The further away you are from your target, the more quality you will experience.
Move slowly and do not touch the ground: this will make it easier to see no more particles around you.
Avoid areas moved with many particles: the flash will reflect in them causing white spots in the photograph, as reflected light in suspended particles.
Hold your breath when shooting: this will avoid the trepidations, since in that environment we move more than we would wish.