Techniques for wide angle underwater photography are presented. Underwater video photography enthusiasts need to utilize supplementary wide angle lenses on their camcorders to achieve the desired results.
The purpose of this lesson is to introduce you to the equipment and basic techniques of wide angle underwater videography.
Table of Contents
The wide angle zoom lens setting on camcorders isn’t truly wide angle. When compared to lenses for 35mm still cameras, the camcorder wide angle setting approximates a normal angle (50 mm) lens. Thus, a supplementary lens is used for wide angle videography.
Supplementary lenses can be added two ways:
- The lens (wide angle adapter) can screw directly into the camcorder lens. This, for example, is the method used with the Gates housings for Hi8 camcorders.
- The wide angle lens may be included in the dome port assembly, which attaches to the housing. This, for example, is the method used with Amphibico housings. A dome port maintains the wide angle view of the lens and reduces loss of corner sharpness in your video images.
Video lights aren’t required for most wide angle videography. Generally, if there is enough light to see your subject clearly, there is enough light to shoot video. Lights are needed, however, at night and inside dark caves or wrecks.
A UR-Pro filter (or the reddish filter provided by the housing manufacturer) is highly recommended. This filter makes your videos much more colorful. Don’t purchase a standard red filter from a camera store because it won’t do the job.
To sum up the equipment – a camcorder, supplementary wide angle lens, reddish filter, underwater housing and dome port are what you need to get started. This basic setup is what many housing manufacturers offer as standard equipment. The main advantage of this system is it covers a wide range of subjects. You can shoot scenics and close-ups.
Focusing For Wide Angle
A dome port acts as a lens. It focuses a virtual image about one foot in front of the port. Even though a subject may be three or more feet away, the camcorder lens (behind the dome port) “sees” the subject as if it were about a foot away. Thus, the camcorder’s wide angle lens must be able to focus down to about one foot.
Your method of focusing depends on the design of your camcorder lens. Standard lenses (author’s term) have a special macro mode. To focus closer than about three feet, you must depress a special macro button. Full range autofocus lenses don’t have a macro mode; the lens will focus from infinity to less than an inch. Let’s discuss focusing methods for these two types of lenses separately. You need only read the section that applies to your particular lens.
Focusing A Standard Lens
Standard lenses are sometimes difficult to focus. Even though the supplementary wide angle lens tends to reduce focus distance, the focus is often at the far edge of the virtual image. Thus, images are not always recorded sharply. In bright conditions, depth of field is often great enough to hide focusing problems. In dim conditions, when depth of field is reduced, images lose sharpness.
Some videographers set the camcorder lens for the macro mode and focus with the zoom control. The zoom, however, often moves past the point of sharp focus too quickly. You can’t stop the zoom at the desired point or you may fail to see the point of sharpest focus. If you use the macro mode and zoom control, use a clip or tie-warp to keep the macro button depressed. Otherwise, if you zoom out of the macro mode, you can’t get back in without opening the housing. At least one housing manufacturer has built a delay in the housing’s electronic zoom control to make focusing easier. Note: You can’t use autofocus with the macro mode.
To focus in the standard (non-macro) mode, try adding a supplementary close-up lens to the supplementary wide angle lens. Several of my photo students have followed this advice and their video image sharpness improved immediately. Because of differences in camcorders and housing combinations, I can’t make a universal recommendation as to what lens to use. Try a #1 (one diopter) close-up lens first. If this doesn’t work, try a #2 and then a #3. Note: You can use autofocus when you use a supplementary close-up lens and the non-macro mode.
Focusing A Full Range Macro Lens
A full range macro lens is definitely the easiest to focus. Set the zoom for wide angle and you can focus on anything from the surface of the lens port to infinity. You can also use autofocus.
If you zoom to telephoto, however, you will lose focus. Even with the supplementary wide angle lens in place, the telephoto setting moves the minimum focus beyond the virtual image.
Auto vs. Manual focus
Some videographers swear by autofocus, others swear at it. I believe autofocus is a valuable tool. As long as you have a high contrast subject in the center of the picture area, autofocus works surprisingly well. In most cases, it focuses faster and more accurately than I can focus manually.
Autofocus often fails when you pan from one subject to another. For example, suppose you were taping two divers about four feet away. When you pan from the first diver to the second, focus is lost when the camcorder “sees” the midwater background between the divers. Then when the second diver is centered, focus jumps from blurry to sharp. However, as long as you don’t aim at midwater backgrounds and pan slowly, autofocus usually works.
Manual focus, of course, locks the focus setting for a specific distance. If you had manually focused for the first diver, the focus wouldn’t have changed when you panned to the second diver. If your housing has a focus control, you can start with autofocus to achieve correct focus. Then, you can switch to manual to lock the focus in place.
White Balance And Filter
In most situations, you can set the white balance for either sunlight (outdoor) or automatic. Experiment with both; different camcorders may give different results.
The UR/Pro filters work well with either sunlight or automatic white balance at depths of approximately 15 to 80 feet. Above about 15 feet, images will be too red if you use the filter. If you can’t remove the filter but you have a white balance control, set the white balance for indoor (artificial light) to reduce the reddish cast. Below about 80 feet, the filter loses much of its ability to brighten color. It holds back light, which reduces depth of field.
Wide Angle Subjects
Wide angle lenses offer excellent versatility. You aren’t locked in on large subjects. You can also shoot wide angle scenes of shipwrecks and close-ups of groupers on the same dive, without making equipment changes. With a full range macro lens, for example, you can shoot close-up subjects pressed against the dome port. (You must, however, keep the zoom set for wide angle; if you zoom to telephoto, you’ll lose focus.)
When searching for wide angle subjects, look for the action. If you see a stingray approaching a diver from behind, start shooting. Then, if the ray and diver interact, you have a more complete story on tape because you anticipated the action. Avoid long, dull and boring scenic pans of distant backgrounds. Isolate a single subject and try to show some action.
Because you can shoot wide angle scenics, wide angle close-ups and anything in between, a wide angle lens is virtually all you need. However, if you wish to shoot extreme close-ups of areas only a couple inches high, you need to remove the supplementary close-up lens and use a flat lens port. This will be covered in a later lesson.