Last updated on April 21st, 2022 at 11:27 pm
A thermal monocular can completely change the nature of a night birding outing. It brings the outdoors to life in low-light settings, allowing you to spot animals when they can’t spot you.
Here are 10 things to look for when buying a thermal monocular:
1. Resolution
The resolution of a thermal monocular refers to the number of pixels in an image.
European brands typically offer resolutions of 384px and 640px, whereas American brands offer 320px and 640px.
Generally speaking, the bigger the resolution, the larger the field of view you’ll see through the monocular.
However, other factors can also influence the field of view, like lens size.
Keep in mind that as you use the magnification feature on the monocular, the resolution will decrease.
This is because zooming in doesn’t adjust the lens, but it zooms in on the screen.
The Global Vision Thermal Imaging Monocular from Amazon.com is a great example of a high-resolution thermal monocular.
This monocular can transmit a high resolution and clarity at maximum magnification, making it a great find.
It has highest temperature tracking and distance measurement, so you’ll be able to spatially position your subject.
2. Magnification
In general, thermal monoculars that have a higher resolution also have higher maximum magnification, because magnification reduces the total resolution.
A low-resolution monocular can only afford to reduce its resolution so much.
Most thermal monoculars offer a maximum magnification between 2x and 20x.
The Pulsar Helion Monocular from Amazon.com is on the extreme end, providing 20x magnification.
If you’re looking for a thermal monocular for birding, aim for one with a magnification of about 7-8x.
This is ideal for most birders, although some prefer even more magnification.
3. Micron Number
The micron number of a monocular is related to its magnification.
A monocular with a lower micron number can have more magnification with the same lens size than one with a higher micron number.
The scope’s sensitivity determines the micron number and usually has a value of about 12-17.
For example, the Pulsar Thermion Thermal Riflescope from Amazon.com has a micron number of 12, a big improvement over old monoculars with micron numbers closer to 35.
Monoculars are now smaller with smaller sensors than they used to be.
4. Cost-Effectiveness
Thermal monoculars vary dramatically in cost, from the multi-thousand dollar Pulsar Helion Monocular to the budget choice of the Bushnell Equinox X650.
The Bushnell Equinox X650 is sold on Amazon, and it captures high-quality video and illuminates a range of up to 650’.
All things considered, you need to weigh the pros and cons of different devices and determine what you’re willing to spend money on and what you’re not.
Choosing a budget monocular may mean sacrificing other good features.
However, on the other hand, choosing an expensive monocular may be overkill for an average birder.
5. Field of View
The field of view of a monocular refers to the territory you can see when you look through the lens.
As a general rule, having a higher magnification will decrease the size of the field of view you’re seeing through your monocular.
Sometimes, it makes sense to go for a monocular with a lower magnification so that you can capture a wider field of view.
Ideally, you’ll purchase a monocular that has a wider range so that you can look at a wider field of view or magnify a smaller area depending on your needs at the time.
It’s beneficial to have both to scan for birds and focus on them once you find them.
Field of view is measured in degrees and ranges from 7 to 20.
For example, the FLIR Scout Monocular from Amazon.com has a 17-degree field of view, wider than average for a thermal monocular.
It also has an LCD screen and a rugged build, meaning that it provides a reliable and consistent clear image without breaking.
6. Eye Relief
Eye relief is a measurement of the distance between the monocular lens and your eye.
Usually, a monocular comes with a rubber eyecup that grants you some eye relief, but you need to make sure the eye relief distance is where you need it to be.
With the wrong eye relief, you’ll see a black ring around your field of view instead of seeing a clear picture.
If you wear glasses, you’ll need more eye relief than people who don’t wear glasses. About 3.5 to 4 inches is usually a good measurement to aim for.
7. Durability
Remember that even if you find a monocular that seems like a great deal, it needs to be durable, or else you’ll be replacing it shortly.
Some monoculars, like the Pulsar Helion Monocular, are completely waterproof and are able to be submerged underwater for up to 30 minutes.
Most have some kind of water-resistant shell.
8. Battery Life
Another important factor to consider in a thermal monocular is the type of batteries it uses and how long the battery power lasts.
Most monoculars have at least four hours of battery life, and the best have at least eight.
For example, the Pulsar Helion Monocular has up to eight hours of battery life as one of the high-end options on the market.
9. Size
Most thermal monoculars are something like 7 x 2 x 2 inches in size, although they vary.
The right size for you will depend on how big your hands are and how and where you plan to use the monocular.
If you want to carry your monocular with you on long hikes, consider buying a smaller model that can easily fit into a pack.
To a degree, bigger monoculars have more power, but make sure you check the exact specifications of the model you’re purchasing rather than making this assumption.
10. Weight
If you plan to take your thermal monocular on long hikes or use it for a long period, remember to look for a lightweight one.
Monoculars typically weigh between 6 oz. and a pound.
While that might not seem like a huge difference, you’d be surprised how much your arms can fatigue after holding a pound of weight up to your eye for long periods.