IR cameras have a shallow depth of field, meaning that anything in front of or beyond your target will be fuzzy, out of focus. Therefore it is very important that you check your focus before capturing the image. This is one of the very few things that you cannot change when you get back to the office and analyze the images.
In the above examples there are elements that can make it easy to focus on. See the nails? See the grout lines?
But what can you do when looking at a barren wall? Easy! The temperature of your hand is usually around 95° F. If the wall is around 70°F, which is pretty normal, then you have approximately a 25° difference. So, leave a hand print on the wall and then focus.
Some cameras, the Fluke TiR, TiR1, and Ti32, for example, have IR Fusion (visible light lens and infrared lens). In the picture-in-picture mode you can see both the IR image and the surrounding visible light context. It’s easy to line up sharp edges that have thermal differences. Windows, doors, ceiling/wall lines, for example, usually provide an opportunity to line up the visible light with the infrared. This makes the task of focusing much easier.
These images were taken with Fluke IR Fusion cameras. Notice that the visible light and infrared lines are matched up. This happens when the infrared image is in focus.
How’s your comfort level in thermography?
(The above comments represent my opinion).
Rod Hoff / Restoration Consultants Inc
Thermography Instructor / IR camera sales
3284 Ramos Circle, Sacramento CA 95827
toll free 888-617-3266 ext 301
Provider of Fluke TiS, TiR, TiR1, Ti, Ti25, TiR27, Ti27, TiR29, Ti29, TiR32, Ti32, TiR3, and TiR4 infrared cameras.
See DEMO www.moistureview.com/demo.html