Back To Top

• Magnification or Power
  Spotting Scopes are referred to by two numbers such as 20x60. These numbers is imprinted on the spotting scope body. The first number is the magnification or power of the spotting scope. With a 20x60 spotting scope, a 20x power means that you are magnifying something 20 times  larger than you would see it with the unaided eye. Please remember that as magnification increases, brightness and field of view tend to decrease.
• Objective Lens Size
  Spotting scopes are referred to by two numbers such as 20x60. These numbers is imprinted on the spotting scope body. The second number refers to the diameter of the objective or front lens. The larger the objective lens size, the more light it gathers, and the brighter the image.
• Exit Pupil
  Refers to the size of the circle of light visible at the eyepiece of a spotting scope. The larger the exit pupil, the brighter the image, and the better they are for low light situations. The exit pupil is calculated by dividing the diameter of the objective lens by the magnification power (a 20x60 model has an exit pupil of 3mm). An exit pupil size of 2 or 3 mm is enough for viewing objects in  daylight, an exit pupil size 5 or 6 mm is for dawn to dusk lighting, and 7 mm for nighttime viewing.
• Field of View (F.O.V.)
  Refers to the width of the viewing area seen through the spotting scopes. This number is imprinted on the spotting scope body. It is defined by the width in feet or meters of the area visible at 1000 yards or meters. Wider field of view make it easier to find and track a moving subject. Generally, F.O.V. decreases as magnification increases. 
• Eye Relief
  Refers to the maximum distance a spotting scope can be held away from the eye and still present the full field of view. For eyeglass wearers,  extended or long eye relief can reduce eyestrain. Generally, a spotting scope with 13 mm or more of eye relief is considered long eye relief.
• Near or Close Focus
  Refers to the shortest distance at which the spotting scope can provide a sharply focused image of an object.
• Prism Glass
  Most optical prisms are made from borosilicate (BK-7) glass or barium crown (BAK-4) glass. BAK-4 is higher quality glass yielding brighter images and high edge sharpness. Generally, higher quality spotting scopes use BAK-4 prisms.

Back To Top

Coatings are applied to lenses to reduce glare and reflection, and to reduce light loss.

• Coated
  A single layer on at least one lens surface.
• Fully Coated
  A single layer on all air-to-glass surfaces.
• Multi-Coated
  Multiple layers on at least one lens surface.
• Fully Multi-Coated
  Multiple layers on all air-to-glass surfaces.

Back To Top