Photography of fish schools is one of the most challenging and adrenaline filled activities an underwater photographer can experience. The spectacular view that tens/hundreds/thousands (yes, there are also such situations), fish that are grouped together into one large mass that moves in a coordinated manner is an impressive sight that is hard to resist.
These are the important factors in filming fish schools, which will affect the result you will receive:
The size of the school, the degree of proximity that the school will allow without dispersing and escaping, the currents and visibility of the site, the location of the school relative to the sun, the speed of movement of the school and its depth, the color of the fish and the degree of light return from them (silvery fish return the flash more than others). In general, as before each photo, it is best to accumulate as much as possible prior information about what you plan to shoot in order to prepare accordingly:
The size of the fish schools: a large school that allows close access will be suitable for photography with your widest lens – fisheye, for example. With the fish eye lens you can shoot from a very close distance and still insert the whole school into the frame. If the school retains the distance and does not allow you to stick to it, a correct selection may be a zoom lens in a range as wide as the Nikon 10-24 mm, Canon 10-22 or similar in terms of range. Poor visibility will require you to shoot from a close distance; otherwise the photo will suffer from a soft look and gloomy colors for the mirror.
Dive planning relative to current is also important. Schools float easily in strong currents. You, on the other hand, will not be able to cope with diving in front of the current and to shoot properly. Make sure to take advantage of the current that will lead you to the school.
The location of the sun in the sky: If you photograph a flock of fish and include the sun in the photo, it will require you to work at closed or closed shutter speeds to avoid over-exposure of the bright areas in the frame. An accompanying result of such a photograph would be, for the most part, silhouettes of fish without seeing their color. It’s fine, as long as you’re aware of it. This will require you to photograph when you are upside down, head up and the fish flock above you.
Whether the school is on the move or is hovering on the spot: a flock of dolphins in motion, for example, will require high shutter speeds of 1 / 125s or more in order to freeze traffic. To shoot a school of barracuda staying in the sun and moving slowly, a shutter speed of 1 / 60s will suffice.
The depth of the school is: A school that will be located at a great depth will require you to choose parameters to suit the situation: high ASA value (caution, noisy photography, especially with a compact camera!), open aperture (notice the depth of the field will be reduced), make sure that it will allow the light of the flash to reach the desired distance, if not increase the flash intensity. With high flash and low shutter speed beware of smudging, which will allow enough surrounding light to reach the sensor.
The color of the fish and the degree of return of light: Silver fish tend to return stronger light than the flash than colored fish. Fine use of the flash will prevent over-exposure and disappearance of details from the body of the silver fish. Colorful fish will allow for a stronger flash. Very dark fish will swallow the light of the flash and it will be very difficult to light them even with a strong flash.
Whether to include a diver in photography: Many photographers like to include a figure of a diver in the background filming fish schools. This is because a diver can add a human element and a sense of interaction with the school, which will fascinate viewers of photography. In addition, the inclusion of a diver in the frame may give scale and proportions to the size of the school. In the case of inclusion of a diver in the frame, it is best to brief the diver before the photo for the desired position in the frame, so that it fits the composition you want and the other elements in the frame.
The position of the flashes (or the only flash): In shooting fish schools, it is best to keep the flashes aside as far as possible to provide a wide flare cover that can illuminate the fish on the front of the frame and its edges. When using a single flash it is best to position it overhead as it is more natural, because the human eye is used to high light coming from the sun.