Several mammalwatchers have recently expressed an interest in buying a thermal imaging scope and I had promised to post a review of the scope I bought in March. This is below. But – if you know as little as I did about this a few months ago – I think it might helpful to start with some general and (perhaps overly) basic information about choosing and using a thermal scope.
Thermal Imaging vs Night Vision
Night vision equipment and thermal imaging equipment are different.
Night vision lets you “see in the dark” by amplifying any available light: it doesn’t work in complete darkness but, with a little star light, can generate a pretty bright view of a night time scene.
Thermal imaging, however, will work in the pitch dark, as it relies on the infrared radiation (heat) that every object – living or not – emits. In fact the view through a scope in the pitch dark is the same as the view on a sunny day because visible light doesn’t come into it.
People talk about thermal cameras and thermal scopes. These are, essentially, the same thing.
Both night vision and thermal imaging allow you to observe animals without disturbing them with a spotlight. You will probably find the view through night vision equipment more natural and authentic than the artificial view through a thermal scope. But you are much more likely to find an animal in the first place with a thermal scope (see below).
Thermal scopes are not cheap. Although you can pick up a first generation scope for a few hundred dollars my understanding is that these are next to useless for finding much smaller than a Buffalo that you are in danger of tripping over. The price doubles – more or less – as you go up a generation and you are probably going to end up paying $2000 or more for a decent scope. I have a third generation scope. Fourth generation is the best currently available for sale.
And that is about the limit of my understanding.
Thermal Scopes: Pros and Cons
I have not used night vision equipment in twenty years to cannot say much about how effective the latest gear is, but I think – for a mammal watcher – a thermal scope must surely be the way to go. There are two reasons. First, thermal scopes will work in the pitch dark, which can be useful inside a bat cave for example. Night vision won’t. Second, and this is more important, thermal scopes don’t just help you to see an animal, it helps you to find them: living things are usually hotter than the environment around them so that temperature differential means they often stand out very clearly – literally like a shining light – when you are scanning with a scope. Much more clearly than they would if you were using binoculars or night vision equipment. And this is true both during the day and the night.
I have been using a scope for the past six months now. I bought one originally to take to Sierra Leone to look for Pygmy Hippos. It worked. And if it wasn’t for the scope I am pretty sure we would never have seen a Pygmy Hippo: they are extremely wary of people and when we eventually put a spotlight on the animal we had been observing it bolted immediately.
I also used it extensively in the Amazon, both day and night. It proved extremely useful at finding quite a few nocturnal mammals, including a variety of rodents large and small, some of which – like this Black-tailed Hairy Dwarf Porcupine: an animal that was high up, partially obscured, very well camouflaged and seemed to be avoiding the light. Even when I knew exactly where it was, it took a good 10 minutes to spot using a spotlight and binoculars!
It was also very useful for finding monkeys and squirrels, especially in the early morning before the trees got too hot (more on this later). It was instrumental in finding Satere Marmosets, Black Uakaris and more. When you start using a thermal scope you realise just how much stuff you cruise straight past that is sitting quietly in a tree watching you.
It also worked very well in the deserts around Joshua Tree when I was looking for small mammals in May: perhaps the most effective type of environment for using thermal scopes (though getting the small mammals to stop moving once you put a light on them is a whole other story). It was also useful in the forest of Thailand and Taiwan, where I found many creatures from roosting bats to sleeping macaques.
Oh, and when you have a thermal scope you get pushed to the front of the trail, canoe, car: it is like an upgrade to Business Class.
Although thermal scopes are great at alerting you to an animals presence, especially before the day gets too hot, they also take some getting used to and can be frustrating. Here are a few things to be aware of.
Getting a view through a thermal scope isn’t satisfying (for me at least). When you look through a scope you are seeing a very artificial view of the world … like looking at a film negative, if anyone remembers what they look like. Here’s a video of a scope being used by fox shooters (which I make no apology for as these are evil Australian foxes, though I am not sure how the shooters could be so certain they were shooting at a fox in the first place given it was 350 metres away…). Anyway, the upshot is that if you are anything like me, you are going to want to see the animal in a spotlight too even though observing larger species through the scope (like Pygmy Hippos) is quite satisfying. Well any view of a Pygmy Hippo is satisfying in my opinion. Which leads me to…
Thermal scopes are great for alerting you to an animal’s presence. But the animals can still be very hard to find. The view through a scope is essentially two dimensional and you have no sense of depth or distance. This is not much of a problem out in the open but as soon as you are looking at a dense patch of forest it gets very confusing. Is that blob of light in a tree you are looking at a squirrel 10 metres away, or a Clouded Leopard 250 metres away. Yes … (eventually) … its a squirrel. So I find myself trying to memorise a pattern of branches that I can use to guide my spotlight to the blob of heat I can see through the scope. This requires practice, a good deal of talking out aloud, and a better spatial memory than I have.
Background temperatures matter. The scope picks up all infrared energy and generates some sort of image that is based – I think – on the average heat of things in view. So looking at an iceberg one day might register the same colour/brightness as looking at a Sahara sand dune the next. At least I think this is how it works. Of course if you put a chunk of ice on the dune, or a heap of blazing sand on the iceberg, you would very quickly see the intruder. What this means is that the scope is most effective when you are looking for warm animals in cooler conditions and is much less effective in environments where the background temps are very close to body temperatures. That said, my scope at least is pretty sensitive to fairly small temperature differences: early morning in the Amazon for example it was pretty obvious whether I was looking at a rock or a mammal, even though both were showing “hot” compared to the trees. By midday this was much harder. I am getting better at differentiating the living from the hot and inanimate, but it is still a learning curve
You are going to study a lot of rocks, wasp nests, sleeping birds... These all give off heat and I lost track of the number of ants nests that excited me in Brazil, or the number of sleeping birds I have waded through thorn bushes to track down in the past few months. I am surprised birders haven’t got into these scopes yet.
Give your eyes a rest: even with the brightness turned down as low as it goes it is hard to look through the scope for longer than 30 seconds or so without losing all night vision for several minutes. So I generally scan with mine in half minute blocks and swap eyes or take breaks between.
The Pulsar XQ50 Qantum Thermal Scope
I did a bit of research before I bought my scope. I decided to look for a Third Generation Scope. These are expensive but by no means the most expensive: in mammal watching currency a fourth generation scope was around the cost of a cruise to Antarctica…. After talking to Richard Webb who had just bought one, I focused on the Pulsar brand.
Quite unusually, Pulsar scopes were cheaper in Europe than they are in the USA. Not sure if this is because of currency fluctuations, import duties or price fixing. But they are not the sort of thing you would be able to import through the mail, as there are some quite strict rules about exporting technology which has many more sinister uses than mammalwatching.
I haven’t directly used any other scopes to compare mine too, but – as you can see from my experiences so far – I have been pleased with the successes I have had.
The two main elements of a scope that determine the quality (and price) are its resolution (the number of pixels) and the refresh rate (which governs how smooth the image will be). The image quality through the Pulsar is clearer than I expected: it is easy for example to ID a Colugo from 50 metres away or a Pygmy Hippo from 100 metres away. And the refresh rate is smooth, though every minute or so the image will freeze for a second or two before refreshing again.
Another factor that impacts the price is the size of the objective lens and the scope’s zoom. This scope has a 50mm lens and a four x digital zoom. If I was to buy a scope tomorrow I wouldn’t pay any attention to the zoom and would go for a smaller (and cheaper) objective lens. I almost always use the scope to locate – rather than watch and ID – a mammal, so I’d prefer a wider field of view than I get with the 50mm lens. Closer focussing would be useful too, which I assume the smaller lenses might benefit from. If you are within 10 feet of a mouse in a bush, for example, you cannot focus in to see where exactly it is, which can be frustrating. So close… so far. For the same reasons I almost never use the zoom: it seems to lose in quality what it gains in magnification. Though I suspect the zoom is much more useful for a hunter who will want to make sure that the fox they are about to shoot isn’t next door’s cat.
The one benefit that comes with a larger lens is an increase in the scope’s range. This is seriously impressive with the Puslar XQ50. I guess the range depends on the relative temperature difference of what you are looking at and the surrounding environment, but in Sierra Leone for example I could pick up the heat signature from an oil drum with a fire inside at least a mile away. Smaller mammals, such as squirrels and mice, are easily visible from 100 metres away in warm conditions.
It takes less than two seconds to turn the scope on and start using it (important when you hear that rustle in the bushes and need to spring into action). It uses four AA batteries that last an impressive 7 hours or so. Though it is seldom they last that long when I am out in the field because the unit has a habit of accidentally turning on (the on/off switch is just a push button). I have taken to undoing the battery compartment every time I put it down.
And, though I haven’t tried it, it should be quite straight forward to connect the output to a video recorder. The very latest models have this video ability built in and give you wifi connection to record video straight to your smartphone.
Finally, it is pretty robust. I don’t think I have dropped it properly yet but that day will come soon… walking in the dark, along a trail, with a scope pressed to my eye, a spotlight in my pocket, and a camera around my neck is a recipe for accidents.
Perhaps the biggest frustration I have had was actually buying one. The Internet is full of suppliers who advertise these things and claim they are in stock… expect they aren’t available for weeks when you actually place your order.
In short, thermal scopes – despite some limitations and the expense – are the single biggest mammal watching breakthrough that I can think of in my lifetime. Other – maybe – than mammalwatching.com !
If you are interested in buying a scope please send me a message as I might be able to get a discount for you.