Despite recent scientific advances to create a hybrid optic called a metalens, glass-based lenses are still the only game in town for full-function telescopes, binoculars, and spotting scopes. Most people know and understand what binoculars and telescopes are and what they’re used for, but what are spotting scopes? It’s actually pretty simple.
A Spotting Scope vs A Telescope vs Binoculars
1. Telescope vs Spotting Scope
A spotting scope is a small or portable telescope. It is used during the day instead of the night. Unlike a traditional telescope, a spotting scope has weatherproofing features to deal with fog, rain, and mist. It includes connectors so it can be mounted on a camera tripod, and the image in a spotting scope is always right side up the way we see things ourselves, instead of upside-down like a normal telescope. It also has a lower magnification as compared to a telescope. Finally, spotting scopes are smaller and do not weigh as much as normal telescopes.
2. Binoculars vs Spotting Scope
Binoculars have two lenses on each end of the instrument, where a spotting scope has one lens at each end. Spotting scopes have greater magnification than binoculars, with greater clarity. Binoculars are lightweight and intended to be handheld. Spotting scopes start at one pound for the smaller ones and quickly increase in weight as the quality and power goes up. Three to four pounds is not unusual for a spotting scope.
The magnification for spotting scopes usually begins where binoculars stop. This lets you see more distant objects, and in great detail than binoculars ever could. But greater magnification means that atmospheric conditions will start to have an increased impact on how well you can see what you’re looking at. Dust, glare, humidity, heat waves, and air current will all exert a tremendous impact on the quality of the image. You should high magnification to view landscapes or objects on high attitudes and at dry climates. When at wet and low attitude climates, consider adjusting to a lower magnification.
What this means in everyday practical terms is that anything over 30x will not always be useful. However, on clear calm days with low humidity, a 60x spotting scope could bring you crystal clear images. Trying to achieve that kind of clarity at magnifications in excess of 60x will be prohibitively expensive, so most spotting scopes end their magnification at that point. There is no need of buying an absurdly expensive telescope that can magnify hundreds of time, yet you are most likely going to limited to a magnification of just 60x
Another aspect to consider with regard to image quality is the optical system. Spotting scopes are designed in such a way that image quality goes down as the magnification goes up. This limitation is common in all models, but varies with the quality of your device. The standard low-cost spotting scopes tend to be more limited in this aspect than the high-end expensive scopes. The premium scopes tend to maintain image quality better than their counterparts even when you increase their magnification. You will have to part with a few more bucks though to get such a high-grade scope.
1. Magnification Numbers
Spotting scopes have three numbers on them that tell you what kind of magnification they have. For instance, if a spotting scope says it is 30-60×80, it means the magnification runs from 30x to 60x and the front lens, called the objective, is 80mm in diameter. The greater the diameter of the objective, the greater the clarity of the image.
2. Objective Glass
If you want to see more detail and a better image quality, then go for a larger objective lens. The size of the objective lens also determines the image quality at higher magnification, where larger is better. In spite of this, make sure that lens is not only large, but also a quality one. If a lens is large but of poor quality, you will still get poor image quality. Under normal circumstances, the clarity of the image will decrease sharply at magnifications over 40x. If your needs require you to get sharp images at magnifications over that, because you are a photographer or something, you will have to spend more to get an objective lens made from special materials such as Fluorite glass, ED glass, HD glass, or APO glass.
Inside a spotting scope, there will be one of two different prisms, used to make sure the image is right side up; a Porro prism or a Roof prism.
1. Porro Prism
Most prisms are Porro prisms. It is an extremely efficient design. It is easy to use, affordable and can accept multiple interchangeable eyepieces. It is heavier than the other prism but it usually has camera adapters, so it can be mounted on a camera tripod.
2. Roof Prism
Roof prisms are slim and compact. They don’t weigh as much as Porro prisms but they’re not as efficient as them either. The efficiency of the prism can be increased if you get one that is phase-coated. Scientists are working on creating even better coatings and lens protection all the time so this part will definitely change. For people who travel or who do not need to use a tripod, roof prisms will probably be the better choice.
Spotting scopes with an attached eyepiece are the lower priced ones. Spotting scopes that use separate eyepieces, swapping out multiple eyepieces for different uses, are the more expensive ones. If a spotting scope is advertised as a “body only” scope, it means it does not include an eyepiece at all. You’ll have to buy the eyepiece(s) separately.
Eyepieces can be single magnification or zooming. Eyepieces that are single magnification have better sharpness and clarity. Zooming eyepieces are easier to use and more convenient. To determine which among the available alternatives is best for you is a decision you’ll have to make based on what you intend to use it for.
Uses of Spotting Scopes
Like binoculars, spotting scopes are used for surveillance, hunting, bird watching, viewing ships, landscapes and other distant objects. They can also be useful for scoring targets, archery and in some cases astronomy. You can take nice images of long distant images using specialized cameras with these devices.
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