A vision of stability

Aids to seeing clearly at a distance have come a long way since the days of the captain’s spyglass. Modern optics and anti-reflective coatings allow us to see with greater clarity, especially in low-light conditions, than was possible even a few years ago.

Until recently one physical barrier to seeing clearly at a distance remained: binoculars with a magnifying power greater than about 7x could not be used on a boat due to the difficulty of stabilizing the image. Even 7-power magnification could be problematic when conditions were moderately rough.

The first solution to this problem was to mechanically stabilize the binoculars. Along these lines, a few specialized stabilized binoculars using spinning gyroscope wheels were built, usually for military applications. Then the Canon Company took another tack (see “Better binoculars,” Issue No. 76, July/August 1996). Rather than try to control the binoculars themselves using the inertial stability of the spinning gyroscopic mass, the company successfully applied the image-stabilizing technology used in its video cameras to binoculars. Its 10 x 30 IS was a groundbreaking product, making the use of 10-power binoculars on a boat practical for the first time. Canon has expanded its image-stabilized line with introduction of 12 x 36 and 15 x 45 binoculars. The image-stabilization system works as well in these higher-magnification glasses as in the original 10 x 30 IS.

Other than the cost, the major drawback of the Canon product was its lack of watertightness. It was advertised as water resistant, but for many sailors using such an instrument when it might be needed most, in tough sea and spray conditions, was out of the question.

Canon’s virtually exclusive position in the stabilized binocular market has recently changed with Fujinon’s introduction of a stabilized, waterproof binocular called the Techno-Stabi. (To the extent that a product’s name matters, Fujinon could surely have found a better name for this product.) The Fujinon company, known for its high-quality and totally waterproof marine binoculars, had previously produced stabilized binoculars, but the unit’s price, size, and weight made it unattractive to marine users.

The Techno-Stabi magnifies the image by a factor of 14, twice the generally accepted maximum for an unstabilized marine binocular. The 14x magnification is matched with 40-mm-diameter objective lenses and 2.86-mm-diameter oculars. The relative brightness is 8.18. Fujinon doesn’t rate them night glasses; however, they perform quite well in dim, if not dark conditions.Different approachFujinon’s approach to image stabilization is quite different from that used by Canon. Two sources of image disturbance occur when binoculars are used on a boat. Vibration or short-term movement is caused by the transfer of vessel accelerations to the binocular, plus any muscular-induced instability. The second is the result of the relatively slow roll, pitch, and yaw of the vessel. Overall correction for the movement of the binocular is accomplished through the action of miniature electric motors that stabilize the optical prism assembly. Changes in azimuth and elevation are detected by two sensors. Two additional sensors detect horizontal and vertical acceleration. The information from the four sensors is combined in a microprocessor whose software computes the composite correction signals to be applied to the two gimbal drive motors. The end result is a clear, steady image, even at 14x magnification.

The Techno-Stabi takes a bit of getting used to. When you look through the binoculars with the stabilization system off, the image will likely be too unsteady to be useful. When the stabilization system is turned on, the visual world changes. The image is suddenly motionless. There is virtually no jitter or other evidence of binocular-induced motion. You will probably wish to adjust the focus since at 14x magnification any inaccuracy in focus is very apparent.

As long as you are looking at a fixed point, everything will appear wonderfully clear and sharp. However, when you scan the distant image, moving in either azimuth or elevation, something strange happens. The binoculars seem to want to keep looking where you had them aimed previously. There is a momentary delay before the image moves and catches up to where you now wish to look.

This lag effect is a consequence of the use of position information in stabilizing the image. Disconcerting at first, the effect rapidly becomes tolerable and with use seems to virtually disappear. The remarkable immunity of the view to the effects of yaw, pitch and roll more than compensates for the momentary lag seen when trying to scan the horizon fast. In any event, the 14x magnification makes a fast scan of questionable value and the amount of image lag does not interfere with any reasonably fast scan rate.

With binoculars, seeing is believing. The seeing with 14 x magnification is remarkable when contrasted with the usual 7x glasses. The image stability allows detail to be seen at distances where the 7x glasses simply cannot provide sufficient visual information.Focus is critical

As noted, the high degree of magnification makes accurate focus more critical than for lower-power glasses. The single focus knob is a delight to usequick, precise, and with the same feel as the controls on a fine camera. Focus using the left eye, and then adjust the right ocular to compensate for any difference in vision between your eyes. From then on fast and precise focus is obtained by simply rolling the focus knob back and forth with your right index finger. The rubber cups on the oculars fold back neatly to allow the user to wear glasses. If you are devoutly left-handed you can hold the binoculars upside-down and focus with your left thumb. The stabilization system is quite happy at any orientation, even on its side.

Using the Techo-Stabi is simple. Slip your hand through the handstrap (at a price of $1,800 list, you don’t want to drop them), press the power-on/stand-by button on the top left of the body and look for illumination of a red-orange indicator on the back of the binoculars, between and below the ocular lenses. With the indicator illuminated, repressing the power button turns on the active stabilization system. The indicator light glows green when the stabilization is on. The system can be returned to stand-by with a second press of the power button. A press of the power off button shuts everything down. Four AA alkaline cells housed in a battery compartment on the underside of the binocular will power the stabilization system for three hours. Power adapters are available that draw power from the ship’s 12-volt system or from a 120-volt, AC source. The battery compartment cover is closed by a cam-action latch and sealed against the entry of water with an O ring. Careful treatment of the sealing surfaces and O ring are advisable to ensure continued water tightness.

The shape of the Techno-Stabi is somewhat unusual when compared with any other Fujinon marine product. There is no conventional center hinge to allow adjustment of the interpupillary distance. This adjustment is made by pivoting the oculars against the rear surface of the main body of the binocular. The objective lenses are close coupled when compared with conventional glasses. At 2.8 pounds, you won’t want to hold these glasses to your eyes all day, regardless of how attractive the scene may be. If what you are seeing is that compelling, find something to rest them on. The neck strap furnished with the binoculars is very well padded, and at first looked as if it was intended to furnish enough buoyancy to keep the glasses from sinking if dropped overboard. We refrained from testing the flotation ability of the strap but did calculate its displacement and found it would take the buoyancy of five such straps to keep the glasses afloat.

The yellow plastic storage case supplied with the glasses is waterproof, gasketed, virtually air tightand it floats! The die-cut plastic foam lining will protect the binoculars against almost any conceivable maltreatment.

The price/value relationship of any binocular depends on the situation in which it is used. Marine binoculars are often used in visual navigation situations in which seeing distant objects clearly can be critical. The sooner you can see what you are looking for, or the sooner you can be certain that what you seek is not there, the safer you will be. So an image-stabilized binocular clearly can have value for the mariner. On the other hand, these glasses are fairly expensive. Only you can judge their worth in your sailing environment. There are many opportunities to spend money on devices that make navigation more precise. Navigation is ultimately visual. Investing $1,800 in seeing with great clarity at a very long distance may be very appropriate for the area in which you navigate.

By Ocean Navigator