Basic primer on night vision equipment?

[v8440]

Hi all,

Is there a basic explanation of night vision principles and equipment? Something that would explain the plain-English meaning of all the different specifications you see when you're looking at nv equipment? I've bought myself a cheap 1st gen monocular from sam's club, and it's pretty impressive for the little bit of money it cost. Still, when I look at the offerings of places that specialize in optics my head spins from all the data.

 

[virtualbeing]

i don't know if there is a basic link to this info. I arbitrarily clicked on of the products they sell at midway. http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=113616

here is the info they post which i found very helpful, hope this helps:


A night vision device works by taking existing light, whether infra-red, moonlight or starlight, and changing it into visible light. This visible light is amplified to the point where it may be viewed in the device's eyepiece. The process, where the existing light (made up of photons) moves through a photocathode tube, changes to electrons that are electro-chemically amplified and then driven against a phosphorus screen to return them to visible light, gives the final image a green hue. Night vision devices are referred to by what "Generation" they are. Each generation has a different type of intensifier tube.

1st Generation amplifies light several thousand times. The image will generally be sharp in the center and slightly blurry around the edges, allowing wildlife observation or for general security use. A 1st generation will hum when on, it may continue to glow for some time after it is turned off, but is the least expensive type of night vision device.
Recognition of a deer on a cloudy night is possible at 75 yards using a 1st generation unit.

2nd Generation has an extra process because a micro-channel plate is directly behind the photocathode tube and amplifies the light many times more than a 1st generation. The image is sharper and brighter.
Recognition of a deer on a cloudy night is possible at 100 yards using a 2nd generation unit.

3rd Generation has a chemical added to the photocathode and a film is added to increase tube life. These changes give excellent low light performance.
Recognition of a deer on a cloudy night is possible at 150 yards using a 3rd generation unit.

4th Generation does not use the film in the 3rd generation but uses a radically different way in which power is supplied to the unit. Image resolution is increased and there is a significant decrease in interference from bright light sources. Range is increased. The US Military does not use the 4th generation designation. These devices are referred to as "Filmless & Gated".
Recognition of a deer on a cloudy night is possible at 200 yards using a 4th generation unit.

Regardless of generation, the image may have some black spots on it. These do not affect the performance or reliability of the device and should not be considered defects.

 

[v8440]

Thanks, that's a very good start! Now if I can make some sense of all the specs that appear on these units I'll be golden.

 

[TabbyMan]

Re: Further data on night vision equipment: GEN3 VS. "GEN4":

However tube life (the Expensive! part) goes from an average of about 10,000+ hours for the GEN3 tubes down to about 2,500+= to the "filmless and gated" aka. "GEN4" tubes. The "GEN4" tubes are about twice the cost of the GEN3 tubes. Price all depands on the tube's electronic performance and any blemishes visible in the field of view. And what's happening in Irag and Afganistan. The Military gets the BEST tubes since it spends only taxcattle money.