- Battery
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- Extremely important for the overall life span and usability of the device
- Sensitivity
- Core Size
- Pixel Spacing
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Lens F Number
- The above 4 items are critical to the performance
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Warranty and Service
- What happens if they have a issue and after the warranty period
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Optical Magnification
- Thermals are very low magnification consider what they actually need
Any thermal device is significant investment and should last you quite a long time. It's important that you understand how and why they work so you can make a good decision on where to spend your money; they are quite technical, and we have compiled the key points that you should be looking at before even looking at an image.
Don’t just look at marketing images they don’t tell the real story, often they are literally just in front of the camera and not even taken in New Zealand.
Battery
The idea of a Thermal Handheld is to use it a lot!! So battery life is very important.
This is probably the most important item that will determine the overall lifetime of the device
Issue 1 – Recharging An internal battery must be recharged from a power source; while on shorter hunts this isn’t an issue, however on a longer hunt this renders the device unusable for quite some time while its being recharged
Issue 2 – Battery Life Batteries fail over time and degrade with usage – once that internal battery fails or doesn’t hold charge for long you have an expensive Brick!
Issue 3 – Battery Performance in Cold Weather Batteries are also affected by cold weather and often the higher run times are quoted at temperatures of 25c or so – How many of you have been night hunting in that sort of temperature?! Real world run times are going to be less than the box says.
Anything with an Internal Battery is a Bad Idea – Replaceable batteries are the best thing to have and totally remove the above issues. Even Pulsar points this out; however, they rely on their own special expensive batteries.
Our Advice – Simply you shouldn’t buy any device that relies on Internal Batteries – PERIOD!
Best Choice? PARD TA Series – these use a simple 18650 Battery – typically worth $35 for a good spare. Plus they are common for a lot of other devices such as torches and headlamps.
The Pulsar is next, they at least have replaceable batteries of their own design; but they are more expensive at $100 per battery and only usable in their own devices.
The remaining brands all have internal batteries!
Sensitivity
One of the key figures in a Thermal Device!
This is called NETD
Simply put this is how well (at a defined set of parameters) the thermal sensor can discern between 2 temperatures. It is measured in Millikelvin (mK). Typically from 25mK to 50mK. The smaller the figure the better the sensor can discern small temperature differences, a lower figure will generally result in a better image, with better contrast
You can read more about this here
- 25mK is Class Leading
- 35mK is 40% WORSE than 25mK
- 40mK is 60% WORSE than 25mK
- 50mK is 100% WORSE than 25mK
Our Advice – A Thermal Device is all about its ability to detect things, Sensitivity is a critical factor especially when you are looking at complex areas - Purchasing a lower performance level is a compromise and where the price doesn’t reflect a lower performance level – why would you?
Best Choice? The PARD TA series uses a Thermal Core with a NETD of <25mK!! – that’s a huge 40% to the next competitor
Anything over 35mK should be avoided totally as it is old technology for a start.
<25mK is the new standard and is critical for thermal performance
Core Size
The more pixels there are, the more they can be used to make nice images, however you will notice that for the same size lens a 640 delivers around half the optical magnification of a 320-400 size core – this is because the lens must focus the ‘light’ over nearly twice the area.
It is more expensive to make a 640 Core vs a 384 Core of course as well Typically, there are 2 main sizes now, 384x288 (384) and 640x480 (640), then some brands are running 320x240 (320) and 400x300 (400) and there are a few other sizes which of course bring cost savings, such as 256x192 (256) and 160x120 (160)
640 Cores have 307,200 Pixels
If we look at the 320-400 class of cores, using the 384 as the standard
384 Cores have 110,592 Pixels
320 Cores have 76,800 Pixels – 30% Less Pixels
400 Cores have 120,000 Pixels - 8% more Pixels
256 Cores have 49,152 Pixels – 55% Less Pixels
160 Cores have 19,200 Pixels - 83% less Pixels
The number of pixels is a key figure directly responsible for the performance of the Thermal Device – The difference between 384 and 400 isn’t much, but a 320 core has nearly 1/3 less pixels which is a significant amount. The last two sizes should be avoided as they offer a vastly lower amount of pixels and would likely lead to disappointing performance against any standard Thermal Device. They do generally appear in a cheaper device, but you should check it meets your needs first in the field.
Our Advice – You are going to want to choose a Device that either has a 384/400 or 640 core. Anything less than this has significantly less pixels to work with and this will affect its overall performance.
Best Choice? The PARD TA Series again!
While the Burris has a slightly larger core at 400 pixels, this is just 8% better in size, the Burris only has a .17 Pixel Spacing which lets it down AND they don’t list the NETD at all – which tends to suggest it’s certainly not at the front of the pack
Pixel Spacing
Another key component in determining the performance of the Thermal Device. This is measured in microns (um), smaller is closer and therefore more pixels per square inch of target, which means more resolution. Over the years this was .25 then we have moved to .17 and now we have .12 as the new standard.
The difference from .17 to .12 is 29% so that is a significant difference
Our Advice – Choose a device that has a .12um core; anything else is based on older technology.
Best Choice? Most of the devices are using .12um cores now which is the new standard.
However several of the Hikvision (OWL Range), All of the Burris and one of the Pulsars are still using the .17 cores.
The Pulsar Axion X30S also uses a smaller core of just 320 pixels, this is some 30% less than the others
Lens F Number
So what does F1.0 and F1.2 mean?
Basically it represents the size of the lens - Just like the pupil in your eye, a larger aperture lets in a lot of light – Any number larger than F1.0 is losing ‘light’ and therefore reducing the performance of the scope
A F1.0 allows 44% MORE light than a F1.2 of the same size
Why do they make F1.2 Lenses – its cheaper, the material they are made out of is expensive, also for larger lenses say 100mm they become quite heavy and bulky too – so sometimes its worth sacrificing some performance.
Our Advice – Choose a device that has an F1.0 Lens. In this size of Thermal Device, there is no need to save weight or size – you are losing performance which added to the core sensitivity will add up to a significant performance loss.
Best Choice? All PARD TA Series have F1.0 Lenses as do Most of the Night Tech and also all of the HikVision devices. Pulsar and Burris both use F1.2 Lenses which provide less thermal light through and contribute to less performance.
Warranty and Service
While electronic devices are quite reliable, these devices are used in the outdoors and weather. You should be looking for a 3 year warranty on any Thermal Device, this is becoming quite standard. However a very important factor is what happens when something does go wrong. Ask the following questions:- How Long is the Warranty For?
- If I have an issue where is it repaired?
- Will they be able to service it after the warranty expires?
- Do they send it away straight away or hold it for one shipment in a month?
- How long will it take?
- All PARD thermals have a 3 year warranty
- We are to our knowledge unique in that we can repair our units in our facilities in Melbourne (We also Repair LabRadars, Longshot Cameras and other items for Civilian and Government Users)
- Yes we are able to repair at a cost after the warranty has expired, we will examine your device and give you a price and if its economic then we can repair it
- We send them straight away
- At the moment with Covid shipping 2-3 weeks
Best Choice? All devices come with a 3 year warranty (Burris didn’t list theirs). The key point to find out is going to be about their servicing abilities and how long it will take – We suggest you ask the above questions.
Optical Magnification
Remember to factor in the Optical Magnification you are looking for – your binos are probably 8-10x – Thermals are generally around 2-5x that’s a huge difference, don’t rely on digital zoom, that’s just making a low-resolution image bigger.
Our Advice – Choose the magnification level you want
How Digital Zoom Works
When you use digital zoom, it ONLY enlarges the pixels AND reduces the image resolution and the image quality. And the further you zoom the worse it gets
The more steps you use in Digital Zoom the worse the image will be from the base optical level – The size of the sensor reduces this at the beginning if it is more pixels recorded, but once the image is smaller than the sensor there aren’t any extra pixels to make up the image and from then its all down hill for image quality.
For example if the 384x288 sensor is on 8 times zoom you are using just 48×36 pixels displayed on your screen at 21×21 pixels for a SINGLE real pixel
Bottom Line – be very wary of claims of huge Zoom ranges as to if they are really usable or not at real world distances; especially with thermals you need to have the base Optical magnification for most of your viewing requirements.
384 Versions
| Brand | Model | Sensor Size | Pixel Size | Lens F | NETD | Optical Mag | FOV - H | Battery Type | Warranty | RRP |
| PARD | TA32-19 | 384x288 | .12 | 19mm F1.0 | <25mK | 2.7x | 13.8 | 1x18650 | 3 Years | $2599 |
| PARD | TA32-25 | 384x288 | .12 | 25mm F1.0 | <25mK | 3.5x | 10.6 | 1x18650 | 3 Years | $2899 |
| PARD | TA32-35 | 384x288 | .12 | 35mm F1.0 | <25mK | 4.5x | 7.5 | 1x18650 | 3 Years | $3299 |
| Pulsar | Axion XM30S | 320x240 | .12 | 30mm F1.2 | <50mK | 4.5x | 7.3 | Pulsar Designed Replaceable | 3 Years | $3399 |
| Pulsar | Axion XQ38 | 384x288 | .17 | 30mm F1.2 | <40mK | 3.5x | 9.8 | Pulsar Designed Replaceable | 3 Years | $4199 |
| Burris | BTH25 | 400x300 | .17 | 25mm F1.2 | Not Listed | 1.7x | 15.4 | Internal | Not Listed | $3549 |
| Burris | BTH35 | 400x300 | .17 | 35mm F1.2 | Not Listed | 2.3x | 11.1 | Internal | Not Listed | $3949 |
| Burris | BTH50 | 400x300 | .17 | 50mm F1.2 | Not Listed | 3.3x | 7.8 | Internal | Not Listed | $4349 |
| Night Tech | XD35 II | 384x288 | .12 | 25mm F1.0 | <50mK | 2.5x | 10.5 | Internal | 3 Years | $3399 |
| Night Tech | XD50 II | 384x288 | .12 | 35mm F1.0 | <50mK | 3.5x | 7.5 | Internal | 3 Years | $3999 |
| Hikvision | Lynx LH19 | 384x288 | .12 | 19mm F1.0 | <35mk | 1.86x | 13.8 | Internal | 3 Years | $2299 |
| Hikvision | Lynx LH25 | 384x288 | .12 | 25mm F1.0 | <35mk | 2.45x | 10.5 | Internal | 3 Years | $2499 |
| Hikvision | Owl OH25 | 384x288 | .17 | 25mm F1.0 | <35mk | 1.7x | 14.88 | Internal | 3 Years | $2799 |
| Hikvision | Owl OH35 | 384x288 | .17 | 35mm F1.0 | <35mk | 2.3x | 10.66 | Internal | 3 Years | $3499 |
| PARD | TA62-25 | 640x480 | .12 | 25mm F1.0 | <25mK | 2x | 17.5 | 1x18650 | 3 Years | $4699 |
| PARD | TA62-35 | 640x480 | .12 | 35mm F1.0 | <25mK | 2.8x | 12.5 | 1x18650 | 3 Years | $5099 |
| Hikvision | Owl OQ35 | 640x512 | .17 | 35mm F1.0 | <35mk | 1.4x | 17.7 | Internal | 3 Years | $4999 |
| Night Tech | XD50 Pro II | 640x480 | .12 | 35mm F1.0 | <50mK | 2.1x | 12.5 | Internal | 3 Years | $5699 |
| Night Tech | XD65 Pro II | 640x480 | .12 | 50mm F1.2 | <50mK | 3.0x | 8.8 | Internal | 3 Years | $6399 |