Why Don’t Laser Rangefinders Work In Fog – In-Depth Guide

People often ask, why don’t laser rangefinders work in fog?

Let’s find out!

Why Don’t Laser Rangefinders Work in Fog?

The problem with lasers is they can be affected by atmospheric conditions such as humidity, temperature, etc. The more of these factors you add together, the worse your results will be. This is why most people recommend using them indoors, where the air is dry and stable.

If you really need to use a laser outdoors, then you should look into getting an IR laser that operates on different wavelengths than visible light. These types of lasers do not rely on the atmosphere to operate correctly, so they will always give accurate readings regardless of weather conditions.

why dont laser rangefinders work in fog

Why Don’t Laser Rangefinders Work In Fog?

Leupold RX-1400i TBR/W Rangefinder Review

Leupold RX 1400i TBR / W Range Finder is a mid-range range finder for bow and rifle hunting. Designed to deliver features at an affordable price.

To give us a closer view, Leupold sent us a review unit. After shooting elk and whitetail with the Leupold Rx-1400i Triton BDC Reticle Rifle Scope, here’s what we found out:

Leupold’s RX-1400i rangefinders are their entry-level models, but they’re actually midlevel rangefinders that pack a lot of useful functionality into them.

The main advantage of the bow is its built-in “bow mode” that calculates an accurate range using the length of the string and the height at which the archer holds the bow. It compensates for the effects of gravity by taking into account the shorter lengths of arrows fired from steeper angles.

For rifles, Leopold refers to this as a true ballistic range (TBR), but other manufacturers call it horizontal component distance (HCD), and Bushnell refers to it as angle range compensation (arc).

If your archery Line of Sight to a target is 45 yards but you’re on very steep ground, you might need to aim as if the target is 35 yards away. The ten-yard difference could result in a significant difference at the target, so angle-compensating ranging is critical for many bowhunters.

If you hunt from a tree stand, even if you hunt flat land, you can still achieve very steep angles.

Steep angles can cause problems for rifle shooters who shoot beyond 300 meters, but usually it is most important for hunters who shoot beyond 300 meters. At that point, bullet fall in many big game cartridges becomes critically important. Like it is for archers who shoot at short ranges.

In any case, Leupold lets one pick “Bow Mode” which offers you an angle-compensating range for archery. It is very easy. Pick Bow Mode and you’re done. It works up to 150 meters, after which the RX 1400i switches to LOS mode.


Leupold’s Rx-1400i Triton Binoculars weigh in at just under 6 oz., and they’re about 4 inches tall, 2.5 inches wide, and 0.75 inches thick. They’re made of aluminum alloy, so they should hold up pretty well against the elements. And if you do get them wet, they’ll dry out quickly because they’re waterproof.

The Fog Factor

The Leupold Rx-1400i Triton Waterproof Rifle Scope is waterproof and fog proof. That means it should not fog up on you. But if it’s foggy out – misty – you may have some trouble. Obviously, the laser beams are having problems with refractions on water particles floating in the mid-atmosphere so the scope can’t do its job properly.

The Red Display

The Leupold Rx-1400i TOLED Rangefinder has a red display that is easy to read even when there’s not enough light. Entry-rangefinders with black screens can be difficult to use at dawn and twilight because they don’t show up well against dark backgrounds.

In fact, in dim light, the RX-1450i’s display is nearly too dark. The RX-1450i has three brightness settings,  leave it on high because it does work best in bright daylight on high.

Under cloudy skies, the red display is really bright and clear — it looks great, partly because Leupold’s optics are so good.

If you’re outside in bright sunlight, the screen isn’t bright enough for you to comfortably read without paying more attention.

The red display is beneficial for most hunters during the most critical times of the day, but it isn’t a slam-dunce if you do most of the hunting at dawn or dusk.

TBR/W Explained

Leupold says that the RX-1400I TBR/W is one of the most powerful rangefinders available for under $200. What does that mean? It means it packs a ton of features into an affordable package.

We’ve already discussed Bow Mode, which appears on your screen as just BOW when you’re using the rangefinder. So, so far, so good.

For rifle use, it seems that the RX-1400 is quite a bit more complicated than the RX-1000.

You can choose from three different shooting positions when using the TBR feature: BAS, HOLD/MOA, and TRIG/MIL. In order to select which position you want to shoot from, you must first determine what type of ammo you’re using and where you’re aiming.

This data lets you select one of 25 cartridge load group settings for your RX-1400I. Wow. Take it easy, Maxcer. You’re not supposed to mess around with these things unless you know what you’re doing!

What do I mean by cartridge load groups?

When it comes to rifle ballistically, the simple math for “true” horizontal distance doesn’t quite work out exactly because the bullets don’t always go straight from the end of the barrel to the target. Instead, they curve downward due to gravity along the path between the two points.

If you want to know whether you can hit an animal at 600 yards, you need to test it out first. However, even though your rangefinder may be able to calculate the distance for you, you still need to practice and verify if you’re actually capable of hitting the target.

The key thing here is that Leupolds is bringing a boost of accuracy to a scope in the $200 price bracket. That’s pretty cool.

TBR Modes


The BAS (Ballistic Aiming System) basically displays the True Ballistic Range when you range an item. This is determined by your bullet’s performance group and is displayed on the screen. Use BAS if you wish to range something and know exactly how far you must shoot.

You would aim accordingly and base your shot on what you understand about your bullet’s ballistic characteristics.

For instance, if you’re shooting something at a steep angle with a 400-yard sight picture, you may have to aim as though the thing is 350 yards away. And the BAS setting would show 350 yards for you.


The HOLD mode calculates your score for each round, just like the BAS Mode, but then it displays your line of sight range in the reticle. At the bottom, it displays a holdover value, which should be the distance from your intended target where you should aim.

MIL and MOA 

The MIL and MOAs are similar to HOLD mode, but they give you the holdover information for mils or minutes of angle (MOA) and how to dial your scopes, if appropriate to your optic.


The TRIG mode provides you with a true line of sight, which means that you can see through walls and obstacles. It also tells you the distance from the camera to the subject.

If you’re interested in the mathematical differences between the two modes, the TRIG function briefly shows the true horizontal distance at its top before displaying the true vertical (height).

You can then compare these numbers against your target bullet size to determine if the rangefinder has tweaked the calculations for you.


If you have a quality firearm with a quality optic, then you can improve your shooting accuracy by taking into consideration the curvature of your bullets’ trajectory.

Leupold has worked with these technologies for years, and they’ve improved upon the concept by increasing the number and refinement of the various groups. For most shooters, it’s probably much more accurate than their skills would suggest.

We hope that this article answered all your questions. If you have any queries feel free to reach out in the comments section below.


  • John Moses

    John is the Editor in Chief here at The Outdoor Stores. His area of expertise ensures that there is no one better to suggest which rifles are most suitable for your hunting experience. He is also available for you to contact him personally to discuss the types of animals you want to hunt and the terrain you will be hunting on. Feel free to read his posts for expert opinion on Rifles, Scopes, Rangefinders, Bonoculars and Monoculars.

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