Fujinon Binocular Models Sold by Company Seven

Choosing Your Fujinon Binocular

The common obvious differences between the Fujinon binocular models are magnification and field of view, physical size and weight, and brightness. There are less obvious design considerations including: Eye Relief (the distance between the observers eye and an eyepiece), Interpupilary Distance (the separation distance between the observers two eyes), binocular feel and balance.

Some of the variables are easy to quantify since mathematical equations can predict the result. Consider for example "exit pupil", this the diameter of the cone of light exiting a binocular. The diameter of exit pupil is easily calculated by dividing the aperture of the binocular by its magnification; hence a 10x 70 mm binocular produces a 7 mm exit pupil, while a 16x 70 mm produces a 4.4 mm exit pupil.

Background: How The Eye Works

A binocular can be thought of as a light funnel, gathering light through its lens and forming that light into a cone entering into the eye. The light exiting the binocular passes through the Cornea of the eye, a curved transparent spherical lens tissue in the front part of the eye. The light passes through the Cornea, then beyond the Iris. The Iris is the diaphragm of the eye much like that of a camera lens in purpose. The Iris is the muscular membrane that regulates the intensity of light illuminating the retina with its nerve sensors (cones and rods) at the back of the eye. When in low light or dark environments it dilates (opens) to as much as about 8 mm on a healthy adult eye to permit a wider diameter beam of light into the eye. Conversely in response to white light the Iris constricts (closes) to as small as about 1.5 mm. The entrance pupil is the black spot in the center of the Iris, this is the opening in the Iris through which light passes.

To demonstrate the effect enter a lit room and look across it to some detailed objects, maybe a rack of books for example. You can probably read titles, recognize some of your favorites with the lights on. Now draw the curtains and turn the lights off, you will immediately sense the loss of capacity to see the books in as much detail but over the course of several minutes you eye will dark adapt, the Iris dilating and so more details will appear. Now turn the light on and feel the discomfort in yours eyes for the first several seconds while the Iris constricts in response to the light. Incidentally, the Iris is less sensitive to red light and that is why we encourage the use of dim red light at star watch activities or at work where night vision must be conserved.

The anterior chamber of the eye is filled with vitreous fluid, a clear jelly-like solution; light passes through the vitreous on it's way through the Lens and to the Retina. After light passes beyond the Pupil it then encounters the Lens, a transparent crystalline biconvex lens also known as the aquula. We can not see the lens of another person without specialized exam equipment, hence it is not illustrated at right. The Lens is supported in place behind the Pupil by small tissues that pull or relax thereby changing the shape of the lens to focus the light onto the Retina at the rear of the eye. The Cornea and the Lens refract the light and focus distant or near objects onto the Retina that lines the inside rear wall of the eyeball. The retina is lined with light-sensitive sensors (cones and rods) that accumulate the visual signal and then transmit the information through the optic nerve to the brain where the signals are processed. And so by dilating and exposing more sensors to the stimulis, then the Iris causes the eye to compensate with increased area what is lacked in intensity can provide reasonably good views of fainter areas at night.

Exit pupil has been one of the more important criteria for users of astronomical binoculars. The 7x 50 mm FMT-SX and 10x 70 mm FMT-SX binoculars for example provide an exit pupil of 7 mm, and in addition to the inherent low light properties the large exit pupil makes them practical for many people to handhold and maintain good alignment of the binocular to the eye, especially on a moving platform such as a ship. But for astronomy in urban areas given the eye's inability to dark adapt in skylight polluted areas, then the large 7 mm exit pupil makes more sense when used at darker sky sites than in the suburbs.

Designations Fujinon Porro prism binoculars offer one or more of three basic design descriptions, each of these with very distinct benefits. These are the indicated by the following suffixes:

• The MT suffix indicates the most basic series of Fujinon waterproof binocular. With superior waterproofing and sturdy corrosion resistant construction, they can be used with confidence under all kinds of conditions.
  

• The Fujinon SX series binoculars guarantee that every lens and prism surface coating in contact with the air is coated with a high technology, durable Electron Beam Coating (EBC) process. The result is an overall brightness factor of 95% across the entire visible spectrum - images up to some 15% brighter than most other high quality binoculars! Testing proved it, and so will your own eyes. The benefit is outstanding vision in low light and at night - an especially important consideration in astronomy and marine applications. Except for electronically amplified optical systems, such as those used in night vision scopes, Fujinon SX binoculars deliver an image that is as bright as is possible with modern optics technologies.
  

• The F suffix indicates Fujinon's high-grade series of flat image plane-type binoculars that encapsulates the best of Fujinon technology. Making the image plane flat enables observation of the marginal area of a visual field, reproduces sharper images with colors that are more true to life, while minimizing distortions and astigmatism. These degrees of perfection are simply no found in other binoculars of these apertures and cost.

  Most Fujinon binoculars provide at least 15 of eye relief, some offer up to 23 mm! In the illustration to the right one can see how Fujinon's long eye relief will accommodate a spectacle wearer. The rubber trim of the eyecup acts as a bumper cushion to protect the eyeglass lens. With the eyecup extended it provides shade preventing light that might otherwise come in from the sides from forming a distraction. With or without the eyecup extended, any user can brace the binocular against their brow or their spectacles for steadiness. While not common, there are some people who have deep set eyes, and wear very thick prescription glasses; this combination of factors may result in a need for so much eye relief that few if any binoculars will permit them to see the entire field of view.

  Full size binoculars are available with a leather covering complemented by slip on rubber covers to protect the objective end rings and prism housing from shock, scrapes and dings. Some models are made available completely clad in rubber. There is not difference however in the degree of waterproofness provided by partial or fully rubber covered models. In fact the giant Binocular Telescopes are painted aluminum housings with no rubber covering, and yet these are suitable for shipboard uses in the most harsh seas.

• The C suffix indicates the incorporation of a magnetic compass with measuring micrometer reticles in the binocular. This is available built into the 7x 50 MTRC-SX and also on the improved 7x 50 FMTRC-SX. An optional battery powered compass illuminator facilitates reading the bearings at night. The idea of a 7x 50 mm binocular with a compass has been popular over many years for use on commercial ships and fishing vessels. These are fitted with textured rubber covering, fit comfortably in you hands, are easy to handle, and what's more they have internal and protective aspects that render them ideal for use at sea.

On the outside, the Fujinon binoculars can be differentiated by their identifying label and by some basic specification, usually field of view. Each is serial numbered too. Fujinon binoculars are supplied with some accessories, with a warranty registration card, an instruction manual translated into five languages: English, French, German, Spanish, and Japanese.

Brief Description of Each Fujinon Binocular

Each factor outlined above about choosing a binocular may be as important a consideration as the other in assuring the long term satisfaction of our customer. However, in an effort to aid you with your search for the binocular of your dreams we have prepared the following brief:

• 8x 30 Binocular Convenient Clarity! Useable from daybreak to dusk - especially for early morning or evening walks in Fall and Winter where daylight is not at its best. Economical yet capable of providing a lifetime of service, multipurpose, handy and easy to use. Observe a distant mountain or study a nearby butterfly! Compact to carry on a walk or for travel. View nature (close in or panoramic), or use at the theater, a concert, or sporting events.
  

• 7x 50 FMT-SX Binocular Incredible detail recognition from dawn to dusk. Bringing a balance of 7.1mm exit pupil, 23 mm eye relief and actual field of view 7-½ degrees wide. With individual focus, these can survive the harshest climates and environments. It is best suited for those who prefer a closer view of distant events: marine use, surveillance, the study of astronomy and other natural wonders. These are about the best value one will find for astronomy since any better 50 mm binocular is likely to cost twice as much or more. Being somewhat hefty it is good news to find these are provided with tripod adapter socket.
  

• 7x 50 FMTR-SX Binocular In optical performance and arrangement this is identical to the 7x 50 FMT-SX binocular described above however, the 7x 50 FMTR-SX adds features that are desired by the mariner; this binocular is fully clad in a durable textured rubber covering to facilitate handling when wet or in extreme cold or icy conditions. The binocular is also provided with captive objective lens covers.
  

• 7x 50 FMTRC-SX Binocular In optical performance and arrangement and in terms of its rubber covering and covers this is similar to the 7x 50 FMT-SX binocular described above. However, the 7x 50 FMTRC-SX adds a built in magnetic compass with an eyepiece ranging reticle. As with the 7x 50 FMTR-SX, this binocular is fully clad in a durable textured rubber covering to facilitate handling when wet or in extreme cold or icy conditions. The binocular is also provided with captive objective lens covers.
  

• 10x 50 FMT-SX Binocular Improved detail recognition from dawn to dusk with notably better performance in twilight conditions than the 7x 50 mm cousin. Shares similar housing and components. Their 5 mm diameter exit pupil can make more sense than that of the 7x 50 for older people, or those in suburbs where eyes may not dilate to beyond 4 or 5 mm. Provided with tripod adapter socket.
  

• 10x 50 FMTR-SX Binocular Same basic model as the 10x 50 FMT-SX mentioned above, but fully clad in a durable textured rubber covering to facilitate handling when wet or in extreme cold or icy conditions. Also, the lens caps of these are captive, this is convenient for quick uses in water spray environments (at sea, etc.). Note, unlike the 7x 50's there is no version of the 10x 50 made which incorporates a compass.
  

• 15x 60 HB Binocular A more compact and versatile binocular arrangement than most of the other Fujinons we offer owing to their center focus and roof prism arrangement. Designed for the hunter and naturalist foremost with good detail recognition from dawn to dusk over great distances, and with notably better performance in twilight conditions than the 10x 50 and their 10 or 12x 60 mm cousins. Provided with tripod adapter socket and with Tripod Adapter although most people on the move find them useful when hand held. Can accept an optional double for use as a 30x 60 mm spotting telescope too!
  

• 10x 70 MT-SX Binocular Bringing nearly two times the light gathering power of a 50 mm binocular to the equation, these are excellent for low light applications including closer distance low light surveillance, panoramic coast watching or mountainside observing. The 10x 70 MT-SX are built to the same mechanical standards as the other premium Fujinon models, and so for uses in harsh climates or heavy duty work these will be superior to most other competing 70 to 80 mm bincoulars selling for under $1,000. The image will be pleasing and bright, but if you wear prescription spectacles or for other reasons prefer longer eye relief, or for astronomical purists the we recommend the 10x 70 FMT-SX. The field of view observed is 5.3 degrees and this is 1.76x the area shown by the 16x FMT-SX. These are a bit hefty - even if a little lighter than the 10x 70 FMT-SX, but some people are able to hand hold these steady enough to get some valid use from them. However, Company Seven recommends use of an optional Tripod Adapter to install these onto a suitable support or stand for longer observing sessions.

• 10x 70 FMT-SX Binocular Bringing nearly two times the light gathering power of a 50 mm binocular to the equation, these are excellent for low light applications including closer distance low light surveillance, panoramic coast watching or mountainside observing, and they have the more perfected imaging properties that make them the best choice in their class for observing large celestial objects including emission nebula and comets. The field of view observed is 5.3 degrees and this is 1.76x the area shown by the 16x FMT-SX. The 10x 70 mm FMT-SX also brings 23 mm of eye relief and this 1.5x increase in eye relief can be a critical factor for some deciding to choose the 10x FMT-SX over others in its aperture range. These too are a bit hefty and with their rubber armor will weigh in a bit heavier than the 10x 70 FMT-SX, but some people are able to hand hold these steady enough to get some valid use from them; their incredible eye relief makes them easier to use too. However, Company Seven recommends use of an optional Tripod Adapter to install these onto a suitable support or stand for longer observing sessions.

• 16x 70 FMT-SX Binocular The poster child of mid aperture astronomical binoculars, selected by Phil Harrington to grace the cover of his book Touring The Universe Through Binoculars which we also stock. These bring nearly two times the light gathering power of a 50 mm binocular to the equation, and higher magnification than their 10x 70 mm cousin making these very well suited for low light applications including longer distance surveillance, coast watching or mountainside observing, observing the Messier Catalog of deep sky wonders (galaxies, nebulae, star clusters, comets). Some of our clients and one employee covered the entire Messier Catalog from suburban settings with this model and with its predecessor the 14x 70 FMT-SX. These are a bit hefty and at 16x few can hand hold these steady and so Company Seven highly recommends use of an optional Tripod Adapter to install these onto a suitable support or stand for longer observing sessions.

• 15x 80 Binocular A more heavy duty, 1.3 times brighter cousin of the above binocular. These are well suited to survive installation on a pedestal exposed to the elements for coast watching, and mountaineering for example.
  

• 25x 150 Binocular Providing 4.6 times the light gathering power of the popular 70 mm models, these are the choice of serious astronomers, for defense and law enforcement border security posts. Nothing else made shows views anything like these, and they are built to provide a lifetime of pleasure.
  

• 25x 150 ED-D/N Binocular A special version of the famous 150 model incorporating advanced technology features. This is sold by Company Seven only for defense and law enforcement to U.S. Government agencies, and to allied foreign governments subject to U.S. Department of State export licensing procedures. Not for sale to mere mortals!
  

• 40x 150 BR Binocular Providing 4.6 times the light gathering power of the popular 70 mm models, and even better twilight performance than the 25x 150, these are the choice of serious astronomers who wish to wish to better view smaller celestial objects, for long distance defense and law enforcement border security posts. Nothing else made shows views anything like these, and they are built to provide a lifetime of pleasure.

High Grade, HB, Standard, and Compass Binocular Model Specifications

Giant Binocular Specifications

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