In this article we will uncover the true benefits of the TORIC 10x50 Binocular and why it may be the best choice for your hunt this fall. Before we do that, let’s ask the question of WHY did the TORIC 10x42 Binocular become the go-to optic for the majority of the hunting community?

# 1  – With optical quality like the TORIC 10x42 a given, it has the ideal size, weight and magnification balance for almost any hunting situation.
#2 – Because everybody else has one.

But, can you do better for your specific hunting needs? Here are some true benefits a 10x50 binocular would have over the ever popular 10x42:

More Light Means More Intel

Like a large bay window that lets in more-light to your house versus a small standard window, the larger objective lens of the binocular has the potential to let in more light to your eye. More light means that you can see more detail…Additional Intel to make better hunting decisions! The exit pupil of a binocular (the white circles you see when holding the binocular out at arms-length) is the same as that window illustration. A 10x50 Binoculars “window of light” is 5mm vs a 4.2mm exit pupil in a 10x42.

Magnification Divided by The Diameter of the Objective  = Exit Pupil Size

Measured Performance of the 10x50 Binocular

By utilizing other optical performance calculations like Relative Brightness & Twilight Factor, it will help tell the story of why a 10x50 Binocular may be the better choice.

Relative Brightness or Brightness Index
To get this performance number, you “Square the diameter of the exit pupil.” So, a 10x42 Binocular which has an Exit Pupil of 4.2 (Magnification divided by Objective) and a 10x50 would have an exit pupil of 5 the calculation would be as follows:
• 4.2 squared = 17.64
• 5 squared = 25

The 10x50 Binocular has a 30% improvement in Relative Brightness over a 10x42 Binocular

Twilight Factor Benefit

However, twilight factor is a more accurate performance measurement for hunters because it takes into account the size of the objective which will be more noticeable during low light conditions. This is calculated by multiplying the size of objective lens by the magnification of the binocular, then finding the square root of the product. This may offend my math friends, but just forget about the square root part, and do the quick math of multiplying the Magnification X Objective to get a quick useable number.

10 X 42 Binocular = 420
10 X 50 Binocular = 500

A 10x50 Binocular has a 16% improvement in Twilight Factor over a 10x42 Binocular

Here’s the bottom line, the larger TF number, the more detail you’ll be able to see in low light. This is why we call the TORIC 10x50 Binocular the Low Light Leader!

Larger Exit Pupil Makes it Easier to Use

Besides the performance calculations, how is a 5mm exit pupil better than a 4.2mm exit pupil?
In some situations, it’s almost impossible to keep the binocular steady. You may be exhausted from climbing that ridge and you’re breathing heavy, or you’re just trying to one-hand the bino and holding it in position is difficult. In these cases, a smaller exit pupil is not as forgiving. A 5mm exit pupil allows your eye more room to move. Keeping the blackout around the edges to a minimum, (especially during times of low-light) it’s important to have and exit pupil exceed the size of your entrance pupil.


In this video, we help explain the relationship between the exit pupil of your optic and the entrance pupil of your eye and why it's important for low-light performance.

Main Advantages of TORIC 10x42 Binocular

Size & weight is by far the biggest advantage over the 10x50. However, how much bigger is it really?  The TORIC 10x50 is 1” taller, ½” wider & approximately 5 oz. heavier than it's 10x42 counterpart.  Take a look at the picture below for more of a side by side visual:

In the case of the TORIC line of binoculars, the Field Of View is greater in the 10x42. How is it possible that a 42mm lens can have a greater field of view over a 50mm you ask? Because the size of the objective has no relationship to binoculars FOV…it’s all designed in the eyepiece.


So, is the 10x50 Binocular the new 10x42 Binocular for hunters? That’s something only you can determine. It truly depends on your specific hunting needs and requirements. Don’t forget, there is no one binocular that can do it all, you may need multiple binos!  To see the full line of TORIC Binoculars visit

Personal Optic Outfitting

If you would like help in choosing the right binocular for your next hunt or adventure, please feel free to call, email, or chat with us online at:

Phone: 631-662-7354