Which endoscope is best for bat surveys?

People often ask which endoscope I use or recommend for bat surveys. For a long time, the RIDGID endoscopes were a must-have for any bat surveyor. However, due to their high cost and low image quality, many bat surveyors (including me) have started to look elsewhere. This blog post explores other options. 

Once upon a time, there was only RIDGID

Since 2013, I have used a RIDGID endoscope for bat surveys. Firstly, the ca300 and more recently the ca350. In 2022, whilst filming for Steve Backshall’s Deadly Predators, I was told that the RIDGID video quality was not suitable for use on TV. The film crew instead brought their own – a £60 endoscope brought from Amazon! How could their endoscope out-perform mine (which cost 10x more)? Turns out the resolution of the RIDGID is 640 x 480; 1080 is needed for TV. 

When BBC Springwatch called in 2023, I was ready with a new endoscope for bat surveys; a Depstech. This was low-cost endoscope (£80) and the BBC used the video from this endoscope on the show. However, the camera probe was so thin it was difficult to hold it still enough to record high-quality videos – see the shaky video below. 

Fast forward to 2024. Several people had recommended the Teslong NTS500, so I thought I would give it a try. The basic setup captured photos and videos which were comparable to the Depstech. I posted the three photos below comparing the endoscopes and concluded (based on the image quality alone) that both the Depstech and Teslong left the RIDGID in the dust. 

I was promised even greater things if I splashed out for the 12.5mm self-focusing camera probe. Frustratingly, none of the UK stores stock this probe, instead I had to import it from the USA. I ordered one and thought I would share a full endoscope review, looking at a range of different aspects, not just image quality. Depstech no longer sell the endoscope I purchased in 2023, so for the rest of this review I will just compare the RIDGID and Teslong.

Cost

Let’s start in the obvious place – cost. At the time of writing (April 2025), the basic endoscope costs for the RIDGID and Teslong are:

Including all of the extras I’ve bought (spare batteries, camera probes and extensions), I have spent about £1000 on RIDGID and £600 on Teslong components.

Image quality

From the above photos, the difference in image quality is clear to see. Here are the specs for each endoscope.

Camera probe

A large factor in image quality is the size/quality of the camera and amount of light the probe provides. Both endoscopes have the option to change probes, which is essential for bat surveys – you never know when you’ll need to inspect a narrow feature or need more length to get to the top of a feature.

As standard the RIDGID comes with a 17mm diameter head and the Teslong a 5.5mm head. RIDGID sell a 6mm head and Teslong sell a 12.5mm self-focusing camera head. 

*plus import duty from the USA. 

Above I shared a comparison of the different endoscopes, using the standard camera probes (17mm for the RIDGID and 5.5mm for the Teslong). However, this isn’t a fair comparison. Let’s look at how both the large and small cameras compare. 

Whilst the Teslong 12.5mm self-focusing camera clearly produces the best quality images, I find that you need to get it quite close to the bat. As a result, the composition of the images isn’t as good as those taken with the 5.5mm camera. In addition, the depth of field is greater on the smaller camera – the Leisler’s bat photographed above was easier to identify using the 5.5mm head than the 12.5mm.  

Dual lens probes

Some of the Teslong camera probes offer two or more cameras – one facing forward and the others at 90 degrees. The quality of the secondary lenses isn’t as good as the main one but this feature is really handy for seeing bats around sharp bends. 

As well as producing different length probes, RIDGID also offer cable extensions. I have both 90cm and 180cm extensions; these are a great addition to my kit, helping me reach many more low features from the ground. Teslong don’t sell extensions, so instead I carry both 1m and 3m probes. Why not just carry the 3m probe? It is a bit cumbersome to coil up this length of probe, when I typically only need less than 1m.  

Using the endoscope

From the manufacture’s website, it appears that these endoscopes were designed for inspecting drains or car engines: Neither endoscope is specifically designed bat surveys. So, how easy are they to use up in a tree?

Single-hand use

The handle and trigger-grip on the RIDGID is very user-friendly. It is easy to hold in either hand and insert the probe with the other. All of the buttons are easily accessible with your thumb. The Teslong resembles a hand-held games console (anyone remember the Game Gear?). It has thin raised grip on the back, which works but i) it has to held in the right hand and ii) doesn’t reassure me that I won’t drop it. Except the power button, all of the buttons are accessible with your thumb. 

Changing probes

Because of the shape of the RIDGID, it is easy to change camera probe up in a tree. When I change the camera on the Teslong, I have to let go of the unit and let it hang on the tether. 

Glare

Both endoscopes suffer with screen-glare, especially on sunny winter days. The smaller screen and slightly raised cowl on the RIDGID makes it slightly easier to see than the Teslong. 

Dirt on lens

Most of the camera heads have concave lens, meaning that they collect detritus when inserted into a cavity. The 17mm RIDGID lens is convex which helps to shed any loose material. The 5.5mm Teslong is flat, which is better than concave but not as good as the 17mm RIDGID. 

Battery

The RIDGID has a removable rechargeable battery (2.5Ah), whereas the Teslong has an internal rechargeable battery (3.5Ah). Both give you plenty of juice for several days of surveying, however the option to have a spare battery for the RIDGID is a benefit. Although, the Teslong uses a standard USB C charging cable which makes it easy to charge when away from the office. The charger for the RIDGID is HUGE and definitely not something I take away with me. 

Memory

The RIDGID uses a standard SD and comes with an 8GB card but can accept up to 32GB. The SD card is tucked away beneath a rubber seal that flaps about – I’ve stuck this down with insulation tape to secure it in place. 

The Teslong uses a micro-SD and comes with a 32GB card. The micro-SD is tucked away beneath a plastic cover. This seems to stay in place but it is difficult to get the card in and out. I am not a fan of micro-SD cards for field work and the spring on the Teslong fires it out at great speed: I have dropped the micro-SD card in the field, luckily I was only on a ladder and was able to find the card on the ground. 

The RIDGID has a small internal memory (235MB), which is very handy if you drop/forget your SD card. The Teslong doesn’t have any internal memory. 

Functions

Auto-power off

Both the RIDGID and Teslong have auto power off options – very handy just in case it turns itself on in the bag. 

Date/time stamp

Both the RIDGID and Teslong allow you to toggle date/time stamps on photos/videos. As this information is saved on the meta-data, I usually have these switched off. The RIDGID has a habit of reinventing Gregorian calendar, giving you results like this. 

Sound

Both the RIDGID and Teslong can record sound along with the video. As I am not in the habit of talking to my endoscope, and as it mainly records the creaking sound of the probe, this is best switched off. 

Attachment points

The Teslong comes with a small metal loop, which allows you to attach a keyring. This allows a climbing carabiner to be clipped in and out, as needed. The RIDGID doesn’t have a loop; I overcame this by fixing a keyring to it with a zip-tie.

Illumination

Both the RIDGID and Teslong allow you to vary the illumination. Annoyingly, when the RIDGID powers, the camera light is off. Considering that you’ll always need some illumination, this is a pain. The Teslong powers on with the light on full brightness – genius! The RIDGID has a display which shows how bright the light is, on the Teslong you have to guess by looking at the light.  

Rotate image

The image RIDGID can be rotated in 90-degree increments, whereas the Teslong only allows 180-degree increments. I’ve never found this useful. It’s much better to correctly orientate the camera probe before inserting into a feature: The 17mm RIDGID camera has a helpful white triangle to help with this. If you position the triangle to face you, what you see on the screen mirrors your movement i.e. left is left and right is right. 

Zoom

The RIDGID offers a zoom function. However, as this is digital, and the resolution is low, it’s not very useful. 

Build quality

This is an area where the RIDGID excels. I dropped a RIDGID out of a tree and it still worked afterwards. Contrast that to the Teslong: within 2 months, it was showing a message of ‘no camera’ when the probe was installed. Needless to say, I won’t try dropping the Teslong out of a tree any time soon.   

The RIDGID can be thrown in and out of bags and survives well. I generally place it into the bag with the handle down, to avoid pressure on the junction between the probe and body. On the Teslong, through fear of damaging the probe, I disconnect it before putting it back into the bag – this gets repetitive and is time-consuming.

Which endoscope is the best for bat surveys?

As I need broadcast quality media, I have switched to using the Teslong. Whilst this may not be a requirement for everyone using an endoscope for bat surveys, having more high-quality images of bats can only be a good thing. Even if a camera probe breaks, it will still cost you less than the RIDGID.

If you need a robust tool which can tolerate being thrown in the back of a van or clipped to a climbing harness, maybe the RIDGID is a better choice. 

Despite switching to using the Teslong, the RIDGID still comes on most trips with me – just in case. Maybe I’m being over cautious or maybe the Teslong still needs to earn my trust. 

Weirdly, when using the Teslong, I had to re-learn how to insert the probe into the tree. I am not sure why it behaves differently to the RIDGID but be prepared for this if you are making the switch. 

July 2026 update

Not long after writing this blog post, Teslong decided to discontinue both the NTS 500 and the self-focusing head. It appears they have replaced the NTS 500 with a NTS 700. From what I can tell, the NTS 700 is similar apart from being slightly larger. The larger screen makes viewing the image slightly easier but is more cumbersome when used up in a tree. They have not replaced the self-focusing head. 

Need experience using endoscope for bats surveys? Have a look at our new endoscope training course.