How to choose binoculars is the most important question that you need an answer to before you can make an intelligent and an informed decision. There are several factors that will determine your selection and on top of it will you need to understand what each feature or specification means in plain speak to know what you want.
Here is my guide to help you understand how to choose binoculars for your use.
Selection based on the use
The first thing that you need to define for yourself is the fact about the potential usage of these binoculars.
Decide if you need the binoculars for
Hunting
Bird watching
Kayaking/canoeing
Boating or Marine
Hiking
Astronomy
Spectator events
All purpose
This use in turn will determine the specifications of the binoculars that you need.
Here is the overview of the main features/specification of the binoculars.
Binocular Magnification or power of the binoculars
If you read the specification of any manufacturer for a pair of binoculars it has the first thing written as NxN for example 10×50 or 7×35. The first number is the magnification which means that how much closer you would be able to see the object. The second part of the equation is that objective lens diameter
Then there are zoom binoculars which have the option of a range of magnification for example 10-22×82 will mean that magnification can be varied from 10x to 22x .
Simple guideline for magnification is
Lower the magnification the more sharp and bright is the object and vice versa
Lower the magnification the more field of view or span you will be able to see and vice versa
Bigger is the objective lens diameter the more light it will receive.
Lens coatings and Image brightness
You will see these three or four shortened versions specified as FC, MC, FMC as the lens coating nomenclature. The coating on the lens means that the lens is coated with material it will increase the light transmission through the lens to your eyes.
Guideline
More light means brighter image
FC – fully coated – Single layer of magnesium fluoride
MC – Multi-coated – Some lenses are multi-coated
FMC – All lenses will be multi-coated.
Focus
Center focus and Individual piece focus
Center focus in binoculars has a single wheel with which you can focus the binoculars rather than having to focus each eyepiece In the Individual piece focus – Each eyepiece will have to be focused individually
Close focus
It is the distance at which the objects are very sharp when viewed thorough the binoculars.
This means the span of area that you can see from one end to the other through your binoculars at a distance of 1000 yards.
Guideline
Large the magnification the smaller is the FOV and vice versa.
For this reason only it is important that you know the use of the binoculars. For birding binoculars it is very important that you have a large FOV as you need to spot the birds in a larger area than you would do an animal in a hunting area.
Waterproof and Fogproof
If you are using the binoculars for outdoor purpose then it is always better to go in for waterproof binoculars especially hunting, birding or boating. If you are using the binoculars only for theater of general use then may be you do not need the waterproof binoculars.
Eye relief for people who wear eyeglasses
Very important feature that you should know if you wear sunglasses. The eye relief is a must if you wear eye glasses to see properly from the binoculars.
This is the distance between your eye and the eyepiece at which you can still see the entire span of the view or the filed of view. Needed for eyeglass wearing people as they will not be able to bring their eyes much closer to the eyepiece.
As the name suggests these binoculars are those which have a digital camera also in-built along with the binoculars. You should know about the following things about the specifications of the digital camera binoculars
Internal memory capacity
SD memory card slot
Instant replay function – This will mean that it has to have a LCD screen
Exit Pupil
This is calculated as the objective lens diameter divided by the magnification and it will mean that a 10×50 bino will have 5 as exit pupil. This gives an indication if image sharpness and rightness
Guideline
A 2.5mm -3mm exit pupil is good during daylight
7mm is what a human eye can easily dilate to means an exit pupil of more than 7mm is not useful
Binocular design
Porro prism or the roof prism.
Porro prism are the older design of the binoculars and the roof prism is the more recent one. As far as viewing capability is concerned there is really no difference. The porro prism has more is more easy to manufacture and in general will cost less than the rood prism.
The rood prism is more compact and trendier.
Guideline
Roof prism binoculars are more rugged as well as more trendy but expensive to make.
Binocular accessories
Neck straps – A must for the ease of carrying as well as for the reason that it will prevent them from falling or you forgetting the binoculars somewhere unattended.
Tripod - This is required if you are using the binoculars with large objective lens diameter normally above 50mm. Till 50 mm the binoculars you will get are relatively Ok to hold in hand but above that they become too heavy to be steady in your hand.
Always visit an offline store and make sure that you feel the binoculars in hand before making a decision about binoculars to buy.