6 key differences of 12×42 vs 12×50 binoculars you probably don’t know

Although not as popular as 8x or 10x magnification models, 12x binoculars still have some advantages and are suitable for specific use. Among 12x types, 12×42 and 12×50 binoculars are the two most well-known. In this article, I discuss and compare the 12×42 vs 12×50 binoculars. 

What are 12×42 and 12×50 binoculars?

The first number indicates the magnification, showing how large objects appear when looking through the binoculars. The second number means the diameter of the objective lens or the size of the lens. Therefore, the 12×42 binocular has a magnification of 12x and the size of the lens is 42 millimeters. For example, Vortex VIPER HD 12×42 Binoculars, Bushnell AW 12X42 Binoculars, and Nikon 7578 Monarch 5 12×42 Binoculars.

Similarly, a 12×50 binocular shows 12x magnification and a 50-millimeter diameter of the objective lens. Some outstanding 12×50 binoculars can be mentioned as Celestron 12×50 Granite Binoculars, Nikon PROSTAFF 5 12X50 Binoculars, Leupold BX-1 McKenzie 12×50 Binoculars,…

12x42 and 12x50 binoculars
A detailed comparison: 12×42 and 12×50 binoculars

Comparing 12×42 vs 12×50 binoculars

First, I will show a general comparison of these two types of binoculars, then dig deeper into each aspect. Finally, I evaluate applications of 12×42 vs 12×50 binoculars based on general needs. 

12×42 binoculars 12×50 binoculars
Size and weight 1.75-2 lb

More lightweight, more compact

1.12-2.8 lb

Heavier, not easy to carry 

Viewing distance Both have a good viewing distance with 12x magnification power
Image stability Both have not good image stability
Field of view Both ranges from about 267ft to 288ft
Image brightness & Low light performance Less notable light-gathering ability Better at image brightness and low light performance
Exit pupil EP = 3.5mm EP = 4.16 mm

Size and Weight

When making the comparison about the size, undoubtedly, 12×50 optics are bigger than 12×42 ones because the diameter of the objective lens is 8 millimeters larger. About the weight, optics with 42-mm objectives generally range from 1.75-2 lb while 50-mm objectives range from 1.12-2.8 lb. Fatigue and one’s capacity to maintain stability are the weight’s two most apparent issues.

Inertia, or the resistance to motion, will likewise be higher in a well-balanced, heavier binocular. Different types of binocular straps and harnesses have been developed to address the fatigue caused by carrying a large pair of binoculars over your neck. It might make sense that a pair of binoculars weighing 1.75 lb is simpler to use and hold than a pair weighing 2.2 lb. 

The ease of use is also depended on the balance of the optics, the distribution of weight onto your arms, and other aspects such as types of binoculars (Roof or Porro). Roof binoculars are more compact and streamlined, lighter weight, and much easier to carry around than the Porro. Also, the way roof prisms are designed makes them more robust, so they will last longer. On the other hand, Porro binoculars are bigger and heavier but bring better images. They have a less light loss, so the images have good contrast and are clear. 

12x42 vs 12x50 binoculars
Size and weight of 12×42 vs 12×50 binoculars

Thus, 12×42 binoculars are more lightweight and more compact than 12×50 of the same type.

Viewing distance

The viewing distance of a binocular depends on its magnification. Both 12×42 and 12×50 binoculars have a magnification of 12x, meaning that when looking at an object through these binoculars, you see this object 12 times larger than looking at it with just your eyes. The magnification number doesn’t indicate the exact distance of viewing but the higher the magnification number, the further the view distance. 

As 12×42 and 12×50 binoculars have the same magnification, these two have the same viewing distance. 12x is a big magnification number, thus, both binocular types represent pretty good viewing distance

Source: Nikon

Image stability

The image stability of a binocular is affected by magnification. The higher magnification the lower the image stability. Holding the optics steady is necessary to make out details. The view appears to move more as the magnification increases. Holding your binoculars steadily might be challenging, particularly if you’re exhausted from a long day in the field. A 12-15x binocular (except for image-stabilized optics) is just too difficult to hold steady and requires a tripod. 

Therefore, for basic activities such as birdwatching, sightseeing, or hunting, I often choose 8x or 10x binoculars. For stargazing, which requires a far viewing distance, I choose 12x. However, I recommend bringing a tripod to foster image stability. Both 12×42 and 12×50 binoculars have the same image stability.

Source: aBinocular.com

Field of view (FOV)

Your binoculars’ field of view is the width of the area you can see. It’s usually described in two ways: angular field of view and linear field of view. The angular field of view is the true angle seen through the optics and is usually measured in degrees. The linear field of view is the width of the area seen and is given in feet observed at 1000 yds.

A larger number for the either angular or linear field of view means you see a larger area. Angular field of view can be used to calculate the linear field of view: just multiply the angular field by 52.5. For example, if the angular field of a particular binocular is 8°, then the linear field at 1000 yds will be 420 ft (8 x 52.5). 

The field of view is related to magnification. In general, a greater magnification yields a smaller field of view. You’ll see less of an area when you increase the scope’s power because you’ll be able to see more particular details of your target or scene. The field of view will widen when you reduce the magnification to low so that you can see more of your surroundings.  12×42 vs 12×50 binoculars have an average FOV of under 300ft, ranging from about 267ft to 288ft. 

Your ability to see the surroundings clearly via your optic will be impacted if you are either too close or too far outside of the recommended eye relief distance. Sometimes exceeding the specified eye relief distance can result in a shadowing or vignetting ring that surrounds the full border of the field of view.

Source: Nikon

Image brightness & Low light performance

Image brightness depends on the size of the lens. The bigger size of the lens, the better the image brightness. A bigger diameter of the objective lens will produce brighter and better quality images due to its more notable light-gathering ability. 

Therefore, between 12×42 and 12×50 binoculars, 12×50 binoculars are better at image brightness as they have a lens size of 50 millimeters. Thus, under a low light environment, 12×50 binoculars perform better than 12×42 ones. 

Source: Amazon

Exit pupil (EP)

The circular light beam that emerges from the optics eyepiece is known as the exit pupil. You can see a bright circle of light on the eyepiece of your binoculars if you hold them at arm’s length and stare through them. The exit pupil is the size of that circle of light. It is computed by dividing the objective diameter by the optical power. For example, 12×42 binoculars have EP = 42/12 = 3.5 mm. 

The exit pupil has often been used as a measure of how bright a binocular is, under the premise that the larger the exit pupil, the more light there is coming out of the eyepiece. Your eye pupils typically open to roughly 2-3 mm in strong light. Your eye must be directly centered above the exit pupil of the binoculars if it is near this value to see through the optics.

Comparing 12×42 binoculars having an EP of 3.5 mm and 12×50 binoculars with an EP of 4.16 mm, 12×50 binoculars show better image brightness. 

Applications of 12×42 vs 12×50 binoculars


For stargazing use, 12×50 binoculars are suggested due to their high light-gathering ability and good quality image. Especially, we often go stargazing under a lack of light conditions, so a binocular with a big size of the lens and low light performance is preferred. Therefore, for stargazing, I recommend using 12×50 binoculars. Additionally, if you want to increase image stability, you can use a tripod as well so that the binoculars can be stabilized during stargazing time.

Moreover, your choice of binoculars depends on the location you choose to stargaze. I recommend a high magnification to some extent, if you see stars in an urban area where the sky is quite bright because of light pollution, you are looking at pinpoints of light,  which will be naturally bright. Gathering too much light will cause the dark sky to appear grey,  reducing the contrast between the subject and the background. However, in a dark sky such as in the countryside, a larger exit pupil is recommended. 

Hunting and birdwatching

For hunting and birdwatching purposes, 8x and 10x binoculars are preferred because they are light and easy for moving and produce less vibrating images. If having to choose between 12×42 vs 12×50 binoculars, I suggest 12×42. As they have a smaller size lens, they are less heavy and more suitable for activities requiring walking and moving a lot. However if you go hunting at night and need a good light-gathering binocular, you can consider choosing 12×50 because you can get better image brightness to determine where the prey is. 


For going sightseeing, people often travel in good weather with enough light so they don’t need binoculars with too good light-gathering ability. Instead, the ones who go sightseeing need convenient binoculars small in size and easy to bring with them. 

Concerts/ Theaters

Night performances and concerts are fairly dark, so I recommend binoculars with a larger exit pupil that offers a bright view. 12×50 binoculars with high optical performance allow you to see even facial expressions clearly. However, 12x types are too large and heavy for concerts and theaters. Smaller magnification from 7x to 10x is suggested for these activities because it is handy, lightweight, and more compact. 


In conclusion, 12×42 vs 12×50 binoculars have the same magnification but different diameters of the objective lens. Therefore, each of them is suitable for specific use. When choosing a binocular, you should consider your needs such as light brightness, weight, or image stability to get the most proper one.