There are times when using binoculars is not enough. With binoculars, some details start to become unclear when the distance reaches 100 feet or more. Luckily, the spotting scope comes to the rescue.
A spotting scope is a portable and small telescope that is usually used for looking at terrestrial objects because it has additional optics that can produce an erect image. However, observance of terrestrial objects is not the only use of a spotting scope for it can also be of help when bird watching, viewing distant activities like boat races, hunting, ranging, shooting and other activities that involve magnification beyond the capacity of a pair of binoculars.
If one is interested in buying a spotting scope, there are various spotting scopes to choose from. But how would one know which spotting scope to buy and what are the features to look for? Before picking which spotting scope to buy, it is important to understand first what a spotting scope is.
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A spotting scope is usually classed into two kinds – a prismatic spotting scope and a catadioptric spotting scope. A prismatic spotting scope has a simple refractor and a lens found at one end while the other end has an eyepiece.
The catadioptric spotting scope, on the other hand, has a mix of mirrors and lenses. A normal telescope has an eyepiece that shows an image backward and upside down.
A prismatic spotting scope comes with an erecting porro prism system that shows an upright image. A catadioptric spotting scope usually comes with a prism that allows observation at a 45 degree viewing angle.
Features of a Spotting Scope
A spotting scope comes into play when the usual pair of binoculars cannot provide the proper magnification to view a certain object. It is important to know the essential features of a spotting scope before one has to decide which spotting scope to buy.
So here are the key features which one should put some consideration into when it comes to a spotting scope:
There are two aspects that one has to consider in order to determine the necessary magnification to be used in a spotting scope. The first thing is the viewing condition of the atmosphere.
The presence of wind, air currents, glare, dust, humidity and heat waves could result a poor quality of image at high magnification. For dry climates and high altitude, high magnification works best while low magnification is not favorable with wet and low altitude atmosphere. The atmosphere likewise has the capacity to reduce the amount of details one can see at a certain distance.
The second point is the spotting scope’s optical system. There is always a reduction in the image quality when magnification goes high and the quality of the optical system dictates how fast the drop off in the quality of the image will be.
Normally, expensive spotting scopes are made of premium optical systems. For common observation, lower magnifications of 30x to 40x is enough.
At high magnifications, the larger the objective lens a spotting scope has, the more likely it can offer a good and detailed image quality. However, the quality of the objective lens also factors in.
Go for good quality rather than the size. The better choice, however, would be a good quality and big objective lens.
The performance of a certain spotting scope is usually commensurate with its price. A low or medium priced spotting scope is enough for usual applications but a high-grade performance can only be expected from expensive spotting scope models.
This refers to the distance between the eyes from the spotting scope’s eyepiece while still being able to see the entire viewing field. This aspect is important for those who are not able to get close to the eyepiece such as eyeglass wearers.
Normally, a person who wears eyeglasses would need 14 mm of eye relief but it goes higher the thicker the glass lens becomes.
This improves the transmission of light and comes in handy in high magnification. A fully coated spotting scope offers good quality but for higher quality and better performance, one should go for “multi-coated” and, even better, “fully multi-coated”.
It is not essential but a close focus of at least 20 feet is helpful when the spotting scope is used with a camera.