Review of the TOPDON TS004 thermal monocular

Review of the TOPDON TS004

A very impressive hand-held thermal – with one significant flaw.

As thermal cameras gradually become increasingly popular accessories for wildlife watchers and hunters, the range of companies producing them is increasing and – as all economics textbooks say should happen – the prices are gradually dropping. That of course can only be a good thing. Currently most decent thermals cost around $1,500 to $3,000, with binocular versions pushing into the low $5,000 range. In other words, the sort of prices that make you seriously question how much use you’re going to get out of them. Jon recently reviewed the Thermal Master T2 imager which you attach to your phone. At a price-point of around $400 in the US, it’s a very interesting proposition. However, there are downsides to using one’s phone as your main imager in the field, and some people, including myself, prefer searching through a monocular (or binocular) rather than looking at a screen. Conveniently, Jon had recently received a free thermal monocular called the TS004 from Topdon (a Chinese company I’d never heard of) and brought it on a recent trip to Minnesota to compare it with the other models he had accumulated. This was another cheaper model, with a quick online search showing that it is currently available in the US for around $390.

On a cold (below freezing) evening in northern Minnesota, Jon, Todd Pusser and I tested four thermal models from different companies on a Grey Gray owl that was hunting voles from a telephone pole (there wasn’t anything else to look at…) and we all agreed that the Topdon performed admirably at picking up the owl, comparing favourably even to Jon’s high-end Zeiss. While it was off to a good start, to fully appreciate the pros and cons of the model would require a dedicated test in the field. As I was shortly off on a mammalwatching trip to Ghana, I took it along to trial under those more strenuous conditions.

A very nice feature of the Topdon is that it is small and light. It fits comfortably in my hand and weighs only just over 300 grams, which is important if you’re going to be lifting it up to your eye all evening. The body is covered in a rubberised plastic that is apparently both waterproof and dustproof. I certainly wasn’t concerned about using it in the rain, and I imagine it’s probably fairly resistant to knocks and drops. It has four buttons on the top: to switch the device on and off, to toggle between viewing modes, to magnify the image, and to take photos or videos. It also has a button on the side that can be used to adjust the focus, though unless you’re going to be looking at animals at very close range, it’s a bit superfluous for wildlife watching purposes.

The most important feature of any thermal imager is image quality and ability to detect warm objects and here the Topdon didn’t disappoint. Compared to my old Pulsar XQ30 – which granted is now about 7 years old – the difference was stark. I would occasionally look through the Topdon and see something smouldering so brightly that I assumed I was looking at a fire, only to discover that it was actually a small mammal. The image was crisp and sharp and at mid-range temperatures in the rainforest it was very good at picking up animals. There was none of the temporary freezing of the image or blowing out when scanning the tops of trees (where everything would appear red) which was standard in my old Pulsar. The Topdon has five modes – white, black, red, fusion (a funky mix of psychedelic colours), and birdwatching, which provides a darker, high contrast mode. I used it almost exclusively on birdwatching mode, both for the greater contrast and because it provided the least bright option – more on that later. The Topdon did less well in the savanna ecosystem in northern Ghana, but we were dealing with temperatures above 38 degrees Centigrade (100 degrees Fahrenheit), at which point everything you look at is hot and all thermal imagers generally cease to be effective.

The blurb in the manual suggested that the Topdon battery lasted 11 hours, which I was rather sceptical about. However, while I didn’t ever fully run it down while using it, the rate of battery loss suggested that it would last around 10 hours, which is excellent. Even more impressive, on one occasion when I had accidentally discharged it completely, the device recharged fully within a mere two and a half hours. According to the manual, this model can pick up objects up to around 400 meters away. Looking at a couple of online reviews, people say it can view large animals at 800 meters, which I’ve no reason to doubt. Frankly most of my thermal use occurs within 100 meters and rarely exceeds 500 meters, so this range is fine for me. However, if you were looking for snow leopards up in the mountains then you might need something with a greater range. Speaking of range, the Topdon does have a distance estimator which is currently in Beta form (very sporadic Beta form in the model I was using). This can be switched on in the menu and will calculate the distance of the object you’re looking at. This is not quite a useful as a laser at showing where the animal is, but, once it’s fully operational, it will at least give you an idea whether you’re looking at a mouse 5 meters away or a deer 500 meters away.

So what about the negatives? Well, the biggest problem I have with the Topdon is that it is just too bright. If you are just using it to scan every 10 minutes or so, then the birdwatching mode works very well – it’s a bit bright but your eye quickly adjusts. However, if you are using it continuously – say walking along a track and scanning every minute – then the brightness becomes a problem. Not only is the image itself too bright, but the battery indicator at the bottom of the screen also gives off far too much light. After an hour of such use I would start to get a headache and would have to hold the device further and further from my eye. In addition to eye-fatigue, the brightness would affect my night vision in that eye, making it harder to switch between the thermal and the torch beam once I had found an animal. Eventually I switched back to my old trusty Pulsar which has a dial on the side which allows you to adjust the brightness all the way down to zero. The Topdon does allow you to select the brightness level between high, medium and low, but the difference between high and low is marginal. The non-birdwatching modes are even brighter and probably unusable for more than a few minutes.

There are a few other smaller gripes I had with the device. While the Topdon allows you to switch off the screen to save power, it doesn’t actually tell you that it’s still operating, leading to it running completely flat on one occasion. A simple ‘screen off’ message would help here. Equally the rubber eyepiece falls off far too easily; it happened to me three times and I finally gave up using it. The buttons on the top of the device are also very sensitive. On a couple of occasions I saw what I thought was a large mammal only to realise that I’d accidentally hit the magnification button and was seeing a squirrel magnified 8x! Additionally, you are supposed to be able to view the image on your phone via an app, but it’s temperamental and didn’t end up working for me. That said, I didn’t bother trouble shooting this for very long.

The TS004 does take both pictures and video which can be downloaded onto a phone or viewed by hooking up to a PC. It’s not a feature I use frequently, and the quality of the images from the Topdon is definitely pretty marginal.

Despite the negatives listed above the Topdon TS004 is a very compelling piece of kit. It combines a high-quality image, a rugged body, light weight and great battery life for a price around 15-20% of what’s on offer from other companies. If you intend to use a thermal for short or sporadic periods of time, it’s well worth considering. For those wishing to use it for extensive ‘survey’ style monitoring, then I would look elsewhere.

If anyone from Topdon is reading this, here is some advice: take the TS004 and add a brightness adjustment dial that can be dropped to a very low brightness setting, glue the eye-piece on properly and refine the distance measure so it works reliably. If you do that and keep roughly the same price point, you will have a product that will be very popular in the wildlife watching and research communities.

It is available from Amazon here :https://www.amazon.com/dp/B0D56CNCW1?maas=maas_adg_563CB8A2E477413ECCD30A56F05D5B93_afap_abs&ref_=aa_maas&tag=maas&th=1