Comparison between thermal imagers based on NETD-value

Not too long ago Jon posted about his experience with the Zeiss DTI6/40. I have commented on this post and since I already wanted to look into the possibilities of upgrading my thermal this year this was as good a time as any to have a better look at the different possibilities. I was looking for one that would be best at detecting mammals at long distances. I wanted to share my thoughts with you guys since it might benefit you as well and I always appreciate more input.

NETD-value

A value of measurement that I had never heard about, but apparently is very important to determine the differences between the ability of thermals to detect objects against a background is the NETD-value. The lower this value is the better the thermal is at detecting objects and dealing with differences in temperature. I think Pulsar does a good job of explaining this further (see: https://pulsarnv.com/blogs/journal/sensor-netd-vs-system-netd). Pulsar makes a distinction between native sensor NETD and System NETD, the latter showing the ability of the thermals software to further enhance the ability of the device to deal with temperature differences. This is not very useful for comparison between brands and I have only focused on the stated native sensor NETD.

In my comparison I have chosen to only focus on this value as in the top devices the difference between refresh rates seems hardly significant and the image quality of all the devices is good. That being said, other features, like the magnification of the device, the kind of lens used and it’s user friendliness can play an important part in making the ultimate decision too. Of course without having the devices in hand and only relying on the information provided by the manufacturers my comparison is certainly not meant to be definitive. Still, I thought people might appreciate the overview.

I have only looked at brands that I already knew about and also would be quite easily able to buy in The Netherlands. This resulted in the following findings:

Pulsar

Their best current device in my opinion is the Telos XP50. Pulsar reports a sensor NETD of <18. Oddly enough their more expensive device, the XL50 has a sensor NETD of <40, which clearly is much higher. Their binocular has a sensor NETD of <25 which is slightly higher as well. Of course other things can be a factor of importance too when it comes to choosing between monocular and binocular which can be a matter of personal preference. Pulsar has introduced a system in which parts of the monoculars can be upgraded later, but I’m not sure how this works in practice.

Zeiss

Their best device for long distance detection seems to be the DTI 4/50 with a NETD of <25. This one has slightly more magnification than the DTI 4/35 because it has a 50mm lens, but is the same in other aspects. Jons device, the DTI6/40 has a NETD of <35 which is slightly higher.

Hikmicro

Hikmicro reports a NETD value of <20 for all its monoculars of the lines “Lynx 2.0”, “Condor” and “Falcon” . I found this very interesting as I have not seen it in the other manufacturers. Obviously this is slightly higher than the Pulsar XP50, but is still a very low  value. It seems their variation is mostly in the focal distance of the lenses used and the resolution. Hikmicro reports the highest detection range for their FQ50 and CQ50L model. For these two models the reported sensor resolution and focal length are identical. I have not looked into what other characteristics separate them exactly. They are both slightly less expensive than the Telos XP50.

The reported lowest NETD-value in Hikmicro’s binoculars beats Pulsars. However there is an interesting difference going on between their most expensive and less expensive models, the same way as Pulsar XL50 versus XP50. The HQ50L offers NETD <15 with a resolution of 640×512. The HX60L offers NETD <18 with a resolution of 1280×1024 and a slightly higher focal length (60mm versus 50mm. This gives the HQ50L a slightly better NETD-value with would make it the preferred choice when considering the price difference, in my opinion. One very cool aspect of these binonculars is that they all have an infrared illuminator, which is a feature the other devices don’t have. This way it is possible to combine both worlds.

I don’t know anyone that has a Hikmicro and was not very familiar with the brand, but it has definitely got my attention. Especially if you are looking for thermal binoculars I would give Hikmicro a better look.

Lahoux

I included this brand as it is easy to get in my country since the company is based here. The lowest NETD-value I could find was <30 for the Lahoux Spotter Elite 35V2.

Leica

I have seen devices of this brand as well in the field. The don’t seem to have that much options. Their currently available model is Leica Calonox 2 View which doesn’t seem to differ from the Leica Calonox 2 View LRF apart from the latter’s range finder. NETD-value is <40.

Conclusion:

Within this comparison it’s clear to me that Pulsar and Hikmicro are the brands to watch. Pulsar offers in my opinion the best monocular for long ranges detection whereas Hikmicro offers the best binocular. This might actually just be the best device for watching wildlife at night in general because of the added benefit of the infrared illuminator. This makes it all the more disappointing to me that I don’t have stores close by that offer a good range of Hikmicro devices.

Feel free to add your thoughts or other devices that you think deserve attention!