You need to decide what you want to do.
You are correct that there are two types, Thermal and light. The "light" class is further dived into near infrared (n-IR) and image intensification (II). n-IR requires external illumination with funnilly enough IR light. This is what a lot of the nature programmes use. You can tell bescause eyes still glow due to reflection. It will work in caves etc. Traditionally uses vacuum tubes with fairly good resolution. A lot of the cheap consumer units use a webcam like digital camer with an IR pass filter. Resolution of those varies

II uses low levels of ambient light hence one name of starlight. They won't work in total darkness but will respond to infrared so you can use an IR light. Can be identified by the noise "sparkles" in the image. There are several "generations" but these are not consistently used particuarly by abvertisers… Proper ones ae expensive and have high resolution

Thermal magers only show difference in temperature. So good for detection but most are not great for identification of what you are looking at. Typically use false colours to represent temperature. Resolution is very variable from less than a hundred pixels in low cost devices to a few thousand in professional equipment costing tens of thousands of pounds. The low resolution units often mix the thermal image with a monchrome video image to improve the apparent resoultion. This does not work in the dark. The frame rate is an issue too. Anything over 9 images a second can be subject to export restrictions so vide rate >25 fames per second) are more expensive. Lenses are typically fixed, Focus is infinity and any zoom id digital with loss of resolution.
These are not best for wildlife.

A versatile and low cost solution is a CCD video camera. These have some sensitivity to n-IR. in fact normally it is blocked by a filter for daylight use. This filter can be removed or on some models moved out of the light path. Sony's name for this is nightshot. A nightshot camera with a LED IR light is one of the best solutions for wildlife. It has high resolution, zoom and recording. If you want to practice in daylight you cna put a IR pass filter on the camera. These also allow you to look through some normally dark materials like black acrylic.

Robert.

Edited By Robert Atkinson 2 on 08/05/2023 09:18:58

I feed and watch hedgehogs in our front garden, we get about six visiting each night thro the summer and foxes plus the odd rat, I bought a wildlife camera to be able to see our visitors. Maybe a wildlife camera would be of use to record what wildlife you have thro the night, being motion triggered it records everything within range and it’s infra red facility means that good pictures are stored to view later. My advice when selecting a wildlife camera, and there is a multitude on the market, is go for a mid price item which should give reasonable quality. Dave W

We have a wildlife camera that you can use for live viewing

its set up on a bird table and streams the feed 24/7 notifys by a message to ones phone when it spots movement and records and/or takes stills

you can also just look at the feed at anytime day or night wherever you are on your phone/tablet/computer

images are great for viewing at large tv sizes

The CV143 tubes were common on the surplus market back in the late 60s. I got one for about 5 bob and hooked it up to an old 9" TV eht power supply. These had a big mains transformer for the eht and a big capacitor to smooth the supply a bit. Handily it had a string of big resistors between eht and ground so easy to tap off about 3 to 4Kv for the tube with a croc clip. But a bit dangerous – that eht supply could kill you as soon as look at you.

The CV143 worked OK but hard to see it as a really useful see-in-the-dark device but it worked well on very dim torch bulbs etc. Very interesting to look up how CV143 tubes were made – very ingenious – they must have been v expensive.

Much later I got hold (cheaply) of an ex military cascade tube. These show up for about £150 to £200 and work off about 4.5 volts to an internal inverter that drives 3 image converter tubes in cascade coupled allegedly by fibre optics. This worked much better with a camera lens at front and a short focus eyepiece at the back. What I found really interesting was to look at the night sky. Not only to see many more stars but also many more small satellites and even meteors. Lent it to someone and never got it back – must have been interesting.

Back then a mate went for a job at Mullard/Philips who made microchannel plate image intensifier tubes for the military etc. Handed a very expensive sample plate to look at he dropped it – and didn't get the job. These tubes could be used as a fast shutter to photograph shells in flight and I was told Mullard had a shed somewhere where shells got shot in one side and out the other for handy snaps.

With apologies … I don’t have time to study it at the moment

[ busy taking debris to the Tip ]

This may be useful for reference: **LINK**

Bestguarder 6×50 mm HD Digital Night Vision Monocular Review

MichaelG.y

Bob, look at your messages John