SAA Policies & Guides
Photography: Getting the big picture.
This panoramic seascape
was lit using a technique
by which the natural
and artificial light
were balanced. A 16mm
fish-eye lens was used.
It is such a privilege to view the underwater world and, particularly with good vis., the panoramic seascape. The so short time of even a long dive tempts many divers to take up underwater photography to capture the scenery few will ever see first hand.
There is an immediate problem, however, and this is the water column in front of the camera, which frustrates our efforts by filtering out both the colour and clarity in our pictures. As with close-up photography the answer lies in reducing the water column to a minimum and there is a way we can do this; in getting the Big Picture we rely on extreme wide-angle lenses that give us in-focus pictures over a large distance.
The lenses.
An extreme wide-angle lens can be defined as any amphibious lens over 20mm or any housed land camera lens over 24mm. Since amphibious lenses are water corrected their angle of view will be smaller than for land camera lenses of the same mm. As an example, the angle of view of the Nikonos 15mm lens is the same as that of a 20mm housed land camera lens.
The Nikonos camera system has three primary lenses designed for its use; the 20mm, 15mm and the 12mm. The 20mm lens has an angle of coverage of 78° (almost twice that of the standard 35mm lens which covers 43.5° ) and it will focus from 40cm to infinity, thereby reducing the amount of water between you and your subject. As it is considerably less expensive than the 15mm and 12mm lenses it has become the most popular wide- angle lens for the Nikonos.
The 15mm lens offers a 94° angle of coverage and focuses from 30cm to infinity. This is without doubt " the lens" for those wide-angle shots of wrecks and seascapes. Both Nikon and Sea & Sea supply 20mm and 15mm lenses for the Nikonos camera. Sea & Sea also make the 12mm F3.5 Fisheye lenses with a coverage of 167° and an infinite depth of field. This new-ish lens may take the place of the legendary 15mm lens in years to come.
It is also possible to convert the standard lens of an amphibious camera to a wide-angle lens by using a supplementary lens. The Nikonos 35mm lens angle of coverage can be almost doubled to 91° by adding the Sea & Sea 16mm super wide conversion lens. This will allow the camera to act as though it has the 15mm primary lens on. Purists will argue that the image quality from such a set up will always be inferior to that of a primary lens, but most will not be able to tell the difference and there is also a great deal of difference in the cost!
The 16mm fish-eye lens is
ideal for wreck and wreckage shots
Sea & Sea’s Motor Marine II-EX has a fixed standard 35mm primary lens to which supplementary lenses can be added to convert it into a wide-angle lens. Wisely Sea & Sea have made their conversion lenses optically similar to the 20mm and 15mm lenses of the Nikonos system. As always the advantage of supplementary lens is that you can remove them underwater thereby extending your choice of picture size.
The Sea & Sea Motor Marine II-Ex and Nikonos cameras are both range finders so you will need a good optical viewfinder to see what the camera sees. When using
wide-angle lenses for close focus pictures you should have an adjustable viewfinder to overcome the problems caused by parallax errors (the viewfinder not showing what the camera is focusing on). It is false economy to skimp on a good viewfinder as your final pictures will suffer from being poorly composed.
The most popular lenses for housed land cameras are the 16mm and 20mm lenses which give angles of coverage of 170° and 96° . When considering which lens to purchase make sure it will fit your housing and that there is a suitable doom port available. With the more popular housings such as the Subal and those made by Sea & Sea there is no problem. There are also a few wide-angle zoom lenses now on the market, which bear further investigation. I would however recommend starting by using a fixed focal length lens at present as they have a much smaller minimum focal distance.
The challenges.
To capture on film large creatures
underwater you will need to
use wide-angle lenses. Here I
have used a housed 24mm lens
and relied on sunlight to illuminate the picture.
There are a few difficulties in wide-angle photography, the most common of which is not getting close enough to your foreground subject. The 16mm housed camera lens at f22 will have a deep of field from the front of the port to infinity as has the Sea & Sea’s 12mm lens. When using either of these lenses you can almost touch your subject, so get in close and then move in closer!!
When taking scenic shots you will have to balance the background which is lit by the sun and the foreground which is lit by artificial light. Learning how to balance these two light scores is the key to great shots.
Lighting wide-angle shots can often be difficult with artificial light (flash) as the flashguns angle of coverage is often less than the lenses field of view. Good flash positioning is essential to prevent uneven lighting or worst still no lighting. Thankfully there are techniques to overcome this problem.
A technical consideration, which can be used to advantage with wide-angle lenses, is that they make subjects in the foreground appear much larger when compared to the background. So, you may need to choose subjects that are unfamiliar to the viewer. For when photographing divers, for example, it is important not to place extremities such as head, arms or legs too close to the lens as they will appear disproportionately large compared to the rest of the body.
I hope these technical difficulties have not put you off wide-angle photography as they all can be mastered. I shall explain how in the second part of this article in two months.
Not all of your subjects need to
be large. This 15cm jellyfish was
taken by a housed 20mm lens.
When taking scenic shots you will have to balance the background which is lit by the sun and the foreground which is lit by artificial light. Learning how to balance these two light scores is the key to great shots.
Lighting wide-angle shots can often be difficult with artificial light (flash) as the flashguns angle of coverage is often less than the lenses field of view. Good flash positioning is essential to prevent uneven lighting or worst still no lighting. Thankfully there are techniques to overcome this problem.
A technical consideration, which can be used to advantage with wide-angle lenses, is that they make subjects in the foreground appear much larger when compared to the background. So, you may need to choose subjects that are unfamiliar to the viewer. For when photographing divers, for example, it is important not to place extremities such as head, arms or legs too close to the lens as they will appear disproportionately large compared to the rest of the body.
I hope these technical difficulties have not put you off wide-angle photography as they all can be mastered. I shall explain how in the second part of this article in two months.
| First clicks | Shooting small 01 | Shooting small 02 | Getting the Big Picture |
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| Building Pictures | Lighting the underwater world | Colouring the Ocean | Balanced Light photography |
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