Porro Prism vs Roof Prism Binoculars: 8 Main Differences

man holding binoculars

I remember I was just having a conversation with another birder on my first few times I was out in the jungle. I noticed that his pair of binoculars was completely different in shape from mine. His had a slightly more compact shape, while mine had a wider lens and had a much brighter sight. I went did some online research on the difference between the two different types of binoculars: Roof Prism Binoculars and Porro Prism Binoculars. Here’s a quick summary of what I found online:

What’s the difference between porro prism and roof prism binoculars? Simply put, the porro prism binoculars have objective lens tubes that are offset from the eyepieces, whereas roof prism binoculars allow light to pass through the objective lenses in two straight tubes, allowing for a more compact design. Generally, the roof prism binoculars are more popular among birders today because of its small and compact size.

With birders and bird watchers everywhere opting for difference choices in their binoculars for birding, this then begs the question on which binoculars is best for you? I did some research online on a more detailed comparison and analysis on their differences, so we can all make a more informed decision on which type to purchase for our birding activities.

black binoculars on white textile near stones
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The Differences Between Porro Prism and Roof Prism Binoculars

Before we all dive into splitting ourselves up into “team porro” or “team roof”, let’s delve deeper into a more technical comparison between the two types. Here’s a quick summarized table of what I compiled from online resources:

In order to understand the differences between the porro prism and roof prism binoculars, we first need to understand what a prism is. A prism is an optical object that can consist of any transparent materials like glass, plastic, and fluorite. Prism can come in different shapes too – triangular, hexagonal or rectangular.

The purpose of the prism is to reflect or refract light in the binoculars. Without the prism, the objects seen through the lens will be laterally inverted (upside down and backward).

Now that we all know what prisms are, let’s see how they compare in their technicalities.

Porro Prism Design Roof Prism Design
Origins of DesignThe conventional design used by bird watchers since the ’60sFirst became popular when introduced by Zeuss and Leitz
Prism DesignPrism alignment is offset outward to the side, forming a zig-zag shape barrelPrism is aligned in a straight line allowing for a straight barrel
DurabilityNot designed to be waterproof and less durableWaterproof and more durable
Ergo DynamicsLess comfortable zig-zag design, heavier in weight and less portableComfortable to hold, lightweight and more portable
Lens CoatingLenses are not coated, but still allows for reflectionLenses are coated for better reflection
Lens PowerLess powerfulMore powerful
Intended UseFor casual usage like bird watching or use at a picnicFor professional usage like birding or hunting
Summary Table of Differences Between Porro Prism and Roof Prism Binoculars

Origins of Design:

The porro prism binoculars have been the conventional design that was used by birders and bird watchers alike since the 1960s. This design is the first instance of use of prisms in our current-day binoculars. The porro prism binoculars were first conceptualized and made in the 19th century by Italian Ignazio Porro, which are still in use to this day.

On the other hand, the roof prism binoculars are the more modern out of both designs, with many intricate machinations that require advanced optical technologies within its casing.

Prism Design:

The porro prism binoculars have a very distinguishable zigzag shape that can make it very easily identifiable as compare to other binocular types. The prism design sends light from the objective lens through a pair of prism that are arranged in a manner to produce a zigzag shape. This allows for quick horizontal movement between the prisms, allowing for magnified and corrected images of objects.

Conversely, the roof prism binoculars have a very streamlined and compact shape, with its objective lens being aligned with the lens. This type of prism design utilizes complicated machinations that allow for a straight path from the objective lens to the lens.


The costs of a pair of porro prism binoculars is generally lower because it does not require much mechanical and optical precision in its manufacturing.

However, a pair of roof prism binoculars is generally much higher than that of the porro prism binoculars simply because it requires more intricate production and assembly of its parts during its manufacturing process.


The durability of porro prism binoculars is much lower than that of the roof prism binoculars. The typical pair of porro prism binoculars is not waterproof and not as durable as a pair of roof prism binoculars.

Ergo Dynamics:

Porro prism binoculars have a zigzag shape that may be difficult for some to hold onto for longer periods of time. Birders may find it difficult to hold up a pair of porro prism binoculars for long periods of time does to its bulkier size and heavier weight.

However, the roof prism binoculars feature a more streamlined, straight barrel design that can allow for a more compact size. The roof prism binoculars also typically be lighter in weight as compared to porro prism binoculars. These attributes contribute to the roof prism binoculars being the more ergo dynamic and comfortable type of binoculars to hold for those who are holding it up at eye-level for long periods of time.

Lens Coating:

The typical porro prism binoculars is not coated with lens coatings to prevent reflection but it is still able to allow for reflection of most light.

On the other hand, the roof prism binoculars is coated with lens coatings on its lenses for better reflection.

Lens Power:

The porro prism binoculars provides a lower lens power as compared to roof prism binoculars that have a higher lens power. This is because many binoculars companies have spent efforts on the roof prism design to perfect it over the years, as people tend to favour the roof prism design over the porro prism design.

Intended Use:

The intended use for porro prism binoculars was for a more casual audience. They are perfect for a picnic to just observe nature and bird watching purposes. As the costs of owning a pair of these binoculars is low, I would recommend these to a person who is just starting out with the basics of birding.

The roof prism binoculars, on the other hand, was designed for more professional use in birding and hunting. As the costs of owning a pair of these is high, I would only recommend it to passionate hobbyist and professionals only.

So now hopefully you will have a more informed decision on whether you will be joining “team porro” or on “team roof” for your birding and bird watching activities. Happy birding!

man looking in binoculars during sunset
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Related Questions

Which Type of Prism Binoculars Is Best For Bird Watching?

Which Type of Prism Binoculars Is Best For Bird Watching? For casual bird watchers who want an inexpensive and entry-level binoculars, I would recommend at porro prism binoculars. However, if you would like to take on a more serious commitment towards birding and bird watching, I would recommend the more serious and professional roof prism binoculars.

Which Type of Prism Binoculars Is Best For Kids?

Which Type of Prism Binoculars Is Best For Kids? For kids, you can consider purchasing a pair of more affordable porro prism binoculars, rather than roof prism binoculars. Leave the more expensive and sophisticated birding equipment (roof prism binoculars) to the adults and teenagers only.

What Magnification of Binoculars Is Best For Birding?

What magnification of binoculars is best for birding? For birding at a far distance, the 10x magnification would be a good fit, but at the expense of a dimmer image and more hand-shake. For birding at a medium to close-range distance, an 8x magnification binoculars will allow for a wider, brighter image with less hand-shake. It is up to you to make a personal choice on which magnification is more suited for your purpose depending on your intended viewing distance.


Justin is a hobbyist birder that hopes to share his birding knowledge with the world. His favorite bird is the Large-tailed Nightjar and he really loves potato chips!

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