Comparison of the Nikonos and Sea & Sea Cameras

Shopping for a scuba camera? You may have the impression that the Sea & Sea Motor Marine II camera line is a less expensive version of the Nikonos V camera. Not true. The Motor Marine has some very nice features, such as autowind, ISO autodetect, and underwater changing of lenses. But it also substitutes lower-quality electronics, aperature, and shutter. These bring the price down. But picture quality is reduced.

Aperature: Light is distorted (diffracted) at corners and edges. The Nikonos V uses the more expensive iris aperature, where 6 curved plates move in or out as the aperature is changed, maintaining a reasonably round opening. The Sea & Sea cameras use the less expensive square aperature with 4 flat plates creating the aperature opening. The 4 right-angles at each corner of the aperature opening diffract light. The picture created by this type of aperature opening can never be as crisp as that of an iris aperature. At small aperatures the ratio of diffracted light to focused light becomes greater, increasing the effects of this distortion.

Shutter: The Nikonos has a curtain shutter. This is a series of very thin metal leaves that are directly in front of the film. These open, then close, to expose the film. This gives an even exposure, and because the shutter leaves are very close to the film, any diffraction of light created by the moving metal edges is not significant. Exposure times are very exact. The Sea & Sea cameras have a peephole shutter. This is a hole just behind the lens that moves past the aperature opening when you click the shutter. Picture quality is less than with the curtain shutter. The edge of the peephole diffracts light as it moves through the opening. The effect of this diffraction becomes more pronounced at fast shutter times and small aperatures. The timing of the exposure is also less exact.

Meter: The Nikonos shows you the exact shutter speed for a perfect exposure. (Or, after changing the aperature, the Nikonos tells you that the exposure is perfect at the current shutter speed.) The Motor Marine II has a "threshhold meter." It lights up when there's not enough light. It doesn't tell you if you're about to overexpose, and doesn't give you enough information to fine-tune an ambient-light fill-flash shot. With print film and casual photography, this can be good enough. But with slide film (routinely used for professional photography), the Sea & Sea cameras can't give you a perfect exposure with ambient light.

Optics: Light is bent as it hits a difference in density. (That's how lenses focus light.) But some of it also reflects. And at each surface, any imperfections will distort the image. So the more lenses you place between your subject and the film, the worse the picture quality will be. A Nikonos fitted with its dedicated 20 mm lens will always take better pictures than a Sea & Sea camera with a 20 mm conversion lens. The same is true of macro sets. The Nikonos uses a single set of lenses, the Sea & Sea cameras use two sets.

Bottom Line: You need to decide what you want from your camera. Do you want lower cost and the convenience of underwater lens changing? Or do you need professional-quality crispness in your images? The Sea & Sea Motor Marine will take good pictures. But compared side-by-side, the best pictures from the Sea & Sea are noticeably less crisp than those taken by the Nikonos. Click to return to the equipment section.