How to Buy Safari Binoculars
This is not an attempt to re-invent the wheel. Many excellent websites are available out there where you could get good, professional advice with a lot of detail to technical aspects. I only intend to help the novice on his way with some down to earth and practical advice in his quest to decide which binoculars to buy, in particular for using them on safari: How to buy safari binoculars.
After clearing up some jargon and technical terms associated with binoculars, I will turn to a few basic decisions which you have to make before considering which one to buy for your safari trip.
By the way, if you're into nocturnal animals and night drives on safari, I suggest you read my article on How to buy night vision devices.
If you're familiar with the technical aspects of binoculars, you can skip the next section and go straight to the section on the 10 decisions.
New Table of Contents
- Jargon and technical terms
- Trade-off between power, objective lens, field of view/vision and brightness of image.
- TEN decisions to make before buying a safari binoculars
- Useful links on binoculars
- Conclusion to How to buy safari binoculars
- Amazon: Porro design binoculars for safari
- Amazon: Roof prism binoculars for safari
- Amazon: Compact binoculars ideal for travel
Jargon and technical terms
In this module I will clarify the technical terminology and other terms associated with binoculars
- Magnification/power: A set of technical detail imprinted on any pair of binoculars could be something like this: 8x42, or 10x50 or 12x50.
The first number (8, 10, 12) is the magnification number, the "power" of the binoculars. The object is magnified by 8, 10 or 12 times, which means that it appears to be 8,10 or 12 times closer than seen with the naked eye.
- Objective lens: The second number (42, 50, 50) is the diameter of the objective lens(in millimeters), i.e. the two big lenses at the front of the two barrels. The bigger the objective lens, the more light is captured, resulting in a clearer and brighter image, which is important when used in fading light or when focusing on something in the shade of a tree. It also means a wider field of view.
- Field of view (FOV): Another set of technical detail which is imprinted on the binoculars, could be something like this: 367 ft. at 1000 yds. This is the field of view, the width of the view at the particular distance. In this case 367 feet at 1000 yards. Could be designated in meters or in degree. Field-of-view is determined by magnification, the objective lens and eyepiece lenses.
- The exit pupil: The exit pupil can be seen by holding the binoculars at arm's length and looking through the eyepieces. The pencil of light you see is the exit pupil. The diameter of the exit pupil determines how much light is transmitted to your eye. The actual diameter of the exit pupil is computed by dividing the diameter of the front objective lens (in millimeters) by the magnification of the binocular. So, in the case of a 7x50 binoculars, the diameter of the exit pupil is 7.1. The diameter of the exit pupil is important in fading light. If it's less than 7mm, your binoculars will not allow enough light through to your eyes (in fading light, that is), unless you're an elderly person, in which case 5mm. will be enough.
- The relative brightness index (RBI) is an indication of image brightness. It is computed by squaring the exit pupil. For example, 7x35 binoculars have a 5mm exit pupil (35/7=5). So their RBI is 25 (5x5=25). A RBI of 25 or greater is considered good for use in dim light.
- Eye relief: For every pair of binoculars, there is an optimal distance between your eye and the eyepiece, which is called eye relief. If your eyes are too close to or too far from the eyepieces, you can't see the whole picture: part of it is blacked out. So, if you happen to wear eyeglasses, you have to make sure the eye relief is at least 15 mm. Except in the case of very expensive binoculars, field of view and eye relief work against one another. If the manufacturer increases the one, it is at the cost of the other. If you do not wear glasses, you do not need good eye relief. If you do wear them, you have to be content with a compromise - unless you're willing to dig deep into your pockets.
- Central focusing knob/wheel: The knob between the two optical barrels by means of which you change the focus when looking at an object.
- Diopter: Every pair of binoculars has a diopter, which is a focus knob (usually at the right eyepiece) that lets you focus one side of the binoculars separately from the other, in order to set the binoculars to accommodate differences in the focusing of your two eyes. Some binoculars have locking mechanisms to prevent the diopter setting from being turned by accident once it had been set. This is a real bonus, although usually found only among expensive ones.
- Coating of lenses: The lenses of all binoculars will be coated with ant-reflective coating, which is applied to enhance the quality of the image. "Coated" simply means a single layer anti-reflection coating on the two external elements (the ones you can see); "Fully coated" means that all air-to-glass surfaces are coated, whereas "fully multi-coated" means all air-to-glass surfaces have multiple layers of coats. Obviously, one would like your binoculars to be "fully multi-coated".
- Waterproofing: Make sure the binoculars are waterproof. A waterproof model will not only be less likely to fog up internally, it will also be better sealed against dust and dirt.
- Close focus: Focusing at a distance is no problem for any pair of binoculars; focusing at close range, however, is a totally different matter. This is important, since sometimes you will be in a situation where close focus is important, in particular if you start getting into birding or even watching butterflies and you would like to appreciate minute details. For birding or butterflies you will have to look for a pair with a close focus range of less than 4 meters.
- The focus speed: If you need the binoculars for watching wild animals, in particular birds, the speed of focus is important. While following a bird in flight, you need to change the focus all the time and if your binoculars do not allow for quick adjustment, you will struggle all the way.
- Prism design: The first thing that strikes you about binoculars, is the apparent difference in two basic types of designs. All binoculars either use "porro prisms" or "roof prisms". The ones using porro prisms are the traditional design where the eye pieces are off center to the barrels, as can clearly be seen in the following photo:
In the case of the ones using roof prisms the eye pieces are in line with the objective lenses and have a sleek design, as can be seen in the following photo:
The advantages of porro prism binoculars are cost (less expensive) and the greater three-dimensional viewing effect, whereas roof prism binoculars are more compact and lighter, but are usually more expensive due to the more complicated manufacturing process. A PC (phase-corrected) roof prism will deliver sharper images than a non PC roof prism.
Trade-off between power, objective lens, field of view/vision and brightness of image.
Power and brightness of image: The brightness of an image is determined by the diameter of the exit pupil. As said above, the exit pupil is computed by dividing the objective lens diameter by the magnification. So, if your binoculars are 8x42, the exit pupil is 5.25. If you want a more powerful pair, like 10x42, your exit pupil will be 4.2. This will deliver less light to your eyes, which translates into less brightness. In bright daylight this will not be a problem, but in dim light as at dawn or dusk, or looking at an animal or bird in the shade of a tree, you will not get the same brightness as with a pair of binoculars with less power/magnification.
(One could argue in the same way by changing the diameter of the objective lens, keeping the magnification the same.)
Higher power not only impacts on brightness, but also on field of view: the higher the power, the narrower the field of vision. Field of view is important: The wider, the easier you can line up your binoculars on a bird in flight or an impala fleeing from a cheetah! However, a wide field of view comes at a price: Vividness. Too wide a field of view will often result in distortion at the edges of the image, whereas narrower field of view ensures sharpness of image. Sacrificing sharpness of image for a wider field of view is never a good choice.
Another problem associated with powerful binoculars is the fact that they are totally useless unless the binoculars are kept perfectly still, which is not easy at all. Several manufacturers, however, make binoculars with image stabilization that electronically reduces movement for steadier viewing, which is helpful when viewing from a moving vehicle or with powerful binoculars. Furthermore, there are tools available (like tripods and tripod adapters) to eliminate some movement.
TEN decisions to make before buying a safari binoculars
Having cleared up the technical stuff, it's time to consider the ten decision you have to make before buying a pair of safari binoculars.
- Decision 1: Usage: Consider what you intend using the binoculars for. This is very important, since it has a direct bearing on what you eventually will buy. Since this article has been compiled with the novice in mind and in particular for people interested in using the binoculars on safari, i.e. for game and bird viewing, I will focus on binoculars best suited for this purpose. I'm visualizing people watching game and birds in nature from a car or a safari truck, or from a game viewing point.
- Decision 2: Personal budget: Make a decision on what you're willing to pay. Even though we've narrowed down the options, you'll still have choices ranging from less than $50-00 to more than $1000-00. I strongly recommend that you do not buy one for less than $200-00. Price does make a huge difference in the case of binoculars. If you do intend using your binoculars for many hours per day (on a safari trip), you will have to be willing to pay much more. One problem with less expensive binoculars is that eye fatigue eventually sets in after a while, which never happens with expensive ones. Check out what Amazon has to offer in the range of $200+.
In any case, if you're not willing to pay more than $100-00 for a pair of binoculars, you could hardly do better than the Nikon 7x35 Action Binoculars.
- Decision 3: Type of prism design: Porro or roof prism design binoculars? The traditional bulky porro design, vs sleek roof design binoculars, which could be very compact indeed, fitting into hand luggage or even a pocket. If you do not intend spending that much, rather go for a porro design. You have a better chance of getting a reasonable quality porro design binoculars without spending that much, than a quality roof design binoculars for the same price.
If size and weight are indeed important to you, you have to go for a roof prism binoculars, but will also have to pay more.
That holds true in particular if you intend buying a compact travel binoculars. In this case very high optical quality will compensate to a degree for the loss of light intake associated with compact binoculars.
- Decision 4: Power: The distance you are from the objects you intend viewing determine the magnification/power you need. For viewing stars you need something totally different than for viewing game or birds. A magnification of 8x is an excellent choice. More powerful than this and you could end up struggling to get a good image. If you do prefer 10x or even more powerful, you will have to consider support in the form of a tripod or tripod adapter.
- Decision 5: Objective lens: One would be tempted to go for big objective lenses, but these have to be considered along with magnification in order to calculate the size of the exit pupil.
- Decision 6: Exit pupil: The exit pupil should not be less than 5mm, but if you're still young, it should be at least 7mm - unless you realize that you will sacrifice clarity in fading light or focusing on animals in the shade.
- Decision 7: Lens coating: Do not settle for "coated" lenses. They have to be at least "fully coated", but ideally "fully multi-coated".
- Decision 8: Eye relief: Do you wear glasses? In that case the "eye relief" has to be at least 15mm.
- Decision 9: Close focus: If you are into birding (or butterfies), you have to look for a pair of binoculars with close focus of not more than 4 meters.
- Decision 10: Field of view: The greater the magnification, the narrower the field of view. If you intend using your binoculars for moving objects like birds or a cheetah in hot pursuit, you should not go for more magnification than 8x.
Useful links on binoculars
Pete Dunne, Director of New Jersey Audubon Society's Cape May Bird Observatory is an authority on the optical needs of birders. Known for his many articles in a host of birding magazines, he is the author of Pete Dunne on Birding, Pete Dunne's Essential Field Guide Companion (as well as many other books), and founding equipment editor for Birding Magazine's "Tools of the Trade." He has been a consultant to Bushnell, Kowa, Leica, Leupold, Nikon, Pentax, Steiner, Swarovski, Swift, and Zeiss.
In addition to a number of useful articles on different aspects of birding, they have a separate, excellent section on binoculars.
Conclusion to How to buy safari binoculars
I discussed the different decisions you have to make when you want to buy a pair of safari binoculars. Although a number of decisions, like budget, intended use and whether you wear glasses or not, are purely personal, all in all one would not go wrong buying one with a magnification of 7-8x and objective lens diameter of 42-50mm. However, if you're not willing to pay $200-00 or more, you might end up with a product not satisfying your needs.
Amazon: Porro design binoculars for safari
Amazon Price: $223.34 (as of 09/20/2008)
Amazon Price: $259.95 (as of 09/20/2008)
Amazon Price: $299.00 (as of 09/20/2008)
Amazon: Roof prism binoculars for safari
Amazon Price: $243.30 (as of 09/20/2008)
Amazon Price: $321.00 (as of 09/20/2008)
Amazon Price: $321.00 (as of 09/20/2008)
Amazon Price: $229.00 (as of 09/20/2008)
Amazon Price: $200.95 (as of 09/20/2008)
Amazon: Compact binoculars ideal for travel
Amazon Price: $74.20 (as of 09/20/2008)
Amazon Price: Too low to display (as of 09/20/2008)
Amazon Price: $97.13 (as of 09/20/2008)
Amazon Price: Too low to display (as of 09/20/2008)
Amazon Price: $91.08 (as of 09/20/2008)