Difference between Porro and Roof Prism Binoculars

In the world of binoculars, there are two basic designs: Porro prisms and roof prisms. If you understand the difference between these designs, you’ll tell at first glance the difference.

Porro prism binoculars have a right-angled bend between the objective lens and the eyepiece, making them take an M shape when standing on their objective lenses. While Roof prism binocular are typically straight, with their objective lens in line with the eyepiece, they take an H shape when stood upright.

Porro Prism Binoculars

These binoculars first appeared in the mid-1800s, designing an Italian optician named Ignazio Porro, and feature two right-angled prisms in each binocular barrel. These days they are considered the more “traditional” binoculars as they were the most common design until the roof prism gained popularity. Porros rely on an external focus mechanism which causes the eyepieces to slide forward or backwards along an outer tube.

Advantages of Porro Prism binoculars:

  • Brighter images due to greater transmission of light
  • Fast-focusing
  • Less expensive to produce
  • Accommodate users with a narrower-set of eyes (including children)

Disadvantages of Porro Prism binoculars:

  • Longer close focus distance
  • Harder to hold for small-handed users
  • Less durable

Roof Prism Binoculars

Roof prism binoculars were developed in the mid-1800s by a German manufacturer who oriented the light-directing prisms inside straight barrels. Due to this design, they produce more reflections than porros due to special coatings applied to enhance the final image’s brightness; these coatings increase binocular costs.

The design leaves almost the entirety of the roof, prism binoculars’ focus mechanism internally. Only the focus knob itself is on the exterior, with most roof prism binoculars labelled as “waterproof”, unlike Porro prism binoculars. At the mid-to-high price range, they dominate the market.

Advantage of roof prism binoculars:

  • Ease of handling
  • Close focusing on advanced models
  • Increased durability and waterproofing
  • Better power-to-weight ratio (a 10x roof prism weighs less than a 10x porro)

The disadvantage of roof prism binoculars:

  • Generally more expensive due to the special coatings in them.

Using binoculars as magnifying glasses

Here’s a fun fact: You can use your binoculars as a magnifying glass in the wild. If you turn your binoculars around, it becomes a magnifying glass, revealing incredible detail in your subject. Treat it like a microscope by closing one eye and looking through one of the objective lenses. It may be awkward but find your topic in the narrow field of view, but you’ll be amazed once you do. So if you have a dull birding session, flip your binoculars and take a closer look at the nearby rocks, plants, insects, feathers and more.

Finding suitable binoculars can be difficult, but we hope this article has helped make the right choice. If you’re still having a hard time, come into Cameraland Sandton, and we’ll help you find the perfect binoculars for the right price.

Original article: Celestron.com

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