I posted a while back that after a fair bit of home work, I bought a cheapie "Night Tech" Thermal imager. It was always gonna be a toe in the water for me, so far I've been quite impressed. I have been reading more about them since and this is a run down on what I've picked up.
There are quite a few specs that need to be taken into consideration before buying a thermal spotter, without knowing the basics you could easily drop a large amount of dosh on something that's gonna disappoint. These are some of the ones I know about.
Imager Resolution: This the amount of thermal capturing "units", called microbolometers that are contained within the imager sensor. The lowest resolution that's seems to be acceptable is the 320x240. The next up from this is 384x288 ( what my unit has ) and after that is the 640x480. The higher the resolution the better the captured image detail. Of all the specs, this one in particular has the greatest influence on $$$.
Refresh rate: This is the amount of times a second the viewer will display a new image. A higher refresh rate gives a smoother view of the heat sources movements. Really you don't wanna go below 25 HZ as the human eye can then detect the break in images. There are some cheap units that run a 9Hz refresh rate which would give an extremely chunky view of what's happening.
Lens Size: This is the physical size of the germanium lens with in the unit. The larger the lens the further the imager can detect a heat source, there is, however a trade off. The larger the lens the smaller the field of view, also costlier. Generally for spotters, the larger field of view is preferred while on a scope the opposite is true.
Display Resolution and type: This is the details on the actual display that can be seen with the eye. It is referred to in pixel quantities. For example the Pulsar XM38 has a 1024x768 AMOLED display. This is considered to be quite high. Once again the higher the resolution the better the detail of the heat source that is captured by the imager.
Pixel Size: The size of the pixels contained within the sensor. Smaller the better. 17um seems to be the accepted with 12um being a step up on some of the Pulsar Axions.
Detection distance: This figure will be given and it needs to be taken with a grain of salt. How it is determined is by the distance the given object will be detected by one imager pixel. So that figure of say 900m for a man size object would probably be halved to give a useful sort of image. There is the ID distance and the detection distance. The detection distance is the distance that you will see something where the ID is where the object can be ID'd.
These figures all contribute to the quality of the viewer. They need to be considered in conjuction with one another. There are certain models that have a lower image sensor resolution yet compensate for it by higher display resolution and smaller pixel size. If you take a look at the monocular that's shown on this page:
https://www.nighthunter.com.au/thermal- ... hd-25-liteThis is the model I went for. It's a common body shape that's used in a lot of different viewers that are manufactured under different brand names eg, Night Tech, Pearl, Guide, Stag, IMax and Iray being a few of them. If you want to go for a known and respected brand eg Pulsar, you wont get the same level of specs for a particular price point than if you go for one of the, can I say " knock off ", brands that I just listed.
On the other hand there are some cheap units that come from respected brands that offer extremely low level specs ( to the point of almost being useless). The Leupold Tracker is probably the best example. If you want get into thermal at entry price point then I feel you're much better going for one of the "knock off" brands.
If you don't mind spending big then by all means go for the premium brands. I know my next purchase will be a Pulsar ( XQ38f ) a way down the track though.
After all this, I'll say that my budget handheld thermal is awesome, it makes hunting so much more enjoyable and I use probably 3 times a week.