# Infrared Thermometer Minimum Distance to Target?



## gregzoll (Dec 25, 2006)

Arm's length is best way to judge. In other words, 2-3 feet, depending on the person.


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## justplumducky (Aug 7, 2009)

gregzoll said:


> Arm's length is best way to judge. In other words, 2-3 feet, depending on the person.


Greg~, I don't get your meaning. I'm wanting to know if the gun can be held as close as one inch from a target, which would make the laser beam diameter 1/12 of an inch in diameter (or just a bit under 3/32"). This gun's distance-to-target ratio is 12:1.

Not really anticipating needing a beam diameter that small (maybe 1/2" diameter), but they say you find all sorts of uses after you buy one.

Thx for your reply.


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## PaliBob (Jun 11, 2008)

justplumducky said:


> .....is there's a minimum distance to target.......


 There is no Minimum distance but for maximum accuracy there is a maximum distance that is dependent on the circular area of the target being measured. Just how much the fan shaped detection beam actually fans out can be approximated with a little DIY experiment:

In a warm room.take a glassof water with
A couple of inches of crushed ice (not cubes) added
Center the laser pointer over the top center of the glass
When the laser pointer is just above the ice bath, it should read 32 Deg
Slowly increase the distance above the glass until the reading jumps >32
This is the height where the detector cone is wider than the glass


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## justplumducky (Aug 7, 2009)

Very cool - thank you PaliBob!


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## Fix'n it (Mar 12, 2012)

i just checked my RAYTEK. from 12' to touching the wall = 0 change.


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## PaliBob (Jun 11, 2008)

The Pali-test is not going to work on the wall. The purpose of using an ice bath in a confined target area (diameter of the glass) against a warm background is that initially the detection area is limited to the ice bath but then as you draw farther away the detection cone area starts to pick up more and more of the warm background so that the IR Thermometer reads increasingly above 32 deg although the laser pointer is still centered on the ice bath.


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