Tips on focusing your BCAM

While we are all here drooling over Kevins new camera and its fantastic resolution, I thought I would post a tip to achieve better resolution with your BCAM.

Aside from anything else, focusing your camera on the subject matter is critical for a quality scan. Inadequate focus changes the apparent temperature reading (if you’re concerned about that). Inadequate focus will hide thermal anomalies under conditions of a low temperature differential. It also shows poor workmanship in your report.

Subject matter that has a high temperature differential is easy to focus and produces a good high contrast scan. Subject matter that has a distinct sharp emissivity differential is easy to focus. However, there are many times when there is a low temperature differential and the entire frame is filled with the same emissivity material. This is frequently the case in slight moisture and air infiltration situations or adverse testing conditions.

As you change the focus, your apparent temperature reading on the camera will change, but does not often accurately focus on the subject. In school it was recommended that focusing by temperature was an option, but I found a more accurate way for these adverse situations.

When you are scanning with your camera in the automatic mode and come across an anomaly:

  1. Focus the camera the best you can.
  2. Turn the camera on to “manual”.
  3. Depending on whether the anomaly is hotter or colder than the surrounding area, press the “+”/"-" until the adjacent background “blacks out”/“whites out” leaving the smallest visible anomaly spot on the screen.
  4. Adjust your focus. As your camera goes out of focus, the spot will disappear. Focus the camera until the spot is the largest possible.
  5. Set your camera back to automatic and snap the picture.

It is also critical to hold the camera steady as possible while depressing the shutter release. I do not know what the shutter speed is for these cameras but I will find out during level 1 training. I do know however, that excessive movement will degrade the scan. You may find that pressing the shutter release button at the top, rather than the bottom will facilitate a better trigger pull.

We spend a lot of time adjusting our palette, however all this can be taking care of with computer software later.
The distance from the subject matter and focus are the only two factors that cannot be controlled with the software. Always get as close to the subject is possible, focus, and hold the camera steady as you can.

Happy snapping!

Good post.

Practice, practice, practice.