Right on the heels of Swarovski’s tM 35, Kahles has followed the parental company into the field of thermal optics. At the start of October 2021, the Guntramsdorf-based company unveiled not one, but two thermal scopes: Kahles TI 25 and Helia TI 35. Let’s take a closer look.
Simple Does It
Kahles Helia TI 25 and 35 scopes sport a remarkably ergonomic and intuitive design. Like the names suggest, Helia TI 25 has a 25mm objective lens, and Helia 35 has a 35-millimeter one. Both models weigh 430 grams (15 oz.) and are compact enough for fatigue-free handling in one hand. Thanks to the rectangular build, there’s no fear of the device rolling away on the dark forest ground.
There are only two control buttons right on top of the housing, so you can make no-look adjustments on the go. Focus can be adjusted manually with an easy-grip wheel on the eyepiece.
The housing is coated in rubber, which protects these devices against bumps and scratches. There is another advantage. Since rubber is a less conductive substance than metal, holding the imager in bare hands won’t be a painful experience even at sub-zero temperatures.
Adverse weather conditions are no match for Helia TI scopes as they guarantee smooth operation from -20 to +50 degrees Celsius (-4°/+122°F). What is more, these devices are also fog- and waterproof.
Kahles Helia TI 25 and 35 scopes are powered by a singular, rechargeable Li-ion battery. Depending on the temperatures of the environment, the battery can last up to 8 hours. The automatic display switch-off will also save up on the runtime.
It takes only 2 seconds for Kahles Helia TI devices to start up and be ready for action.
Sensor Properties
- uncooled VOX sensor
- 384×288 px sensor resolution
- 17 μm pixel size
- 35 mK thermal sensitivity (NETD)
The sensor at the heart of Helia TI scopes is made of uncooled vanadium oxide. The 384×288 sensor resolution is what’s expected in this price segment, right in line with all competitor scopes like DD Optics Nachtfalke IR 50, Liemke Keiler-25 LRF, and Night Pearl Scops 25 ELITE.
Thermal sensitivity of less than 35 mK puts these Kahles thermal imagers a class above Swarovski tM 35 (60 mK). The disparity between better sensor quality and a lower price point makes sense if we consider the manufacturing costs. While Swarovski tM 35 was entirely built in Austria, Kahles outsourced Helia TIs to Asia. These thermal imagers were designed and produced in close cooperation with a Chinese manufacturer with plenty of experience in this field.
Screen Properties
- OLED screen
- 1024×768 px display resolution
- 1x, 2x, 4x digital zoom
- 3 color palettes
- automatic turn ON/OFF
Moving on to the screen properties. A high-resolution OLED display (1024×768 pixels) is ready in only 2 seconds. Kahles also employed a tilt and motion sensor that is akin to SwaroLight. The intelligent screen turns on and off automatically. When the action starts, the screen will light up by itself, there’s no need to press any buttons. It will surely save up battery life.
Optical magnification depends on the model – 1.7x on Helia TI 25 and 2.3x on Helia TI 35. But both offer the same digital zoom options: 1x, 2x, 4x. The image enlargement can be adjusted super-fast with the 2 buttons on top of the imager. There is no need to open and browse through the menu.
The user can toggle between 3 color modes: White Hot, Black Hot, and Red Only. The choice comes down to personal preference and hunting situation as one mode may reveal more details than others. Since this is also a top-priority setting, it can be changed with a simple press of the 2 control buttons.
The minimalistic menu lists only 5 settings for a straightforward operation (e.g. image brightness, contrast, calibration). The 3 fast settings that we previously mentioned are color mode, digital zoom, and focus. These can be changed directly, with the use of the two perfectly placed control buttons and a focusing wheel.
Like nearly all current thermal imagers in the private sector, Kahles Helia TIs have a 50 Hz display frame rate. The human eye interprets anything above 30 Hz as a smooth and continuous movement.
What are the differences between TI 25 and TI 35?
Apart from the obvious difference in objective lens diameter, these 2 Helia scopes offer different FOVs and optical magnification.
| KAHLES Helia TI 25 | KAHLES Helia TI 35 | |
| Objective lens | 25 mm | 35 mm |
| Optical magnification | 1.7 | 2.3 |
| Field of view (m/1000m) | 26 | 19 |
| Field of view (ft/1000yds) | 78 | 56 |
| Price* | 2200 EUR | 2500 EUR |
*As of November 2021. Product price may vary per market and inclusion of VAT.
As we can see, TI 25 model offers a wider field of view and is, therefore, better suited for fast target acquisition.
On the other hand, TI 35 is the perfect choice for reliable identification of animals and other heat-emitting subjects thanks to high detail resolution.
Accessories in the Box
Kahles Helia TI 25 and TI come with a number of accompanying products that will maximize the user experience.
- Objective lens cover
- Carrying strap
- Neoprene protective cover
- USB-C charging cable
Warranty
The warranty period on these thermal imagers is 3 years from purchase. This is the industry norm for nearly all thermal optics.
Kahles Helia TI 25 and 35 are manufactured in China. One of the advantages of choosing Kahles is that all post-sales services are performed in Austria.
The new HELIA thermal imaging products will be available in stores starting November 2021 for a retail price of €2200 (TI 25) and €2500 (TI 35).
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