How Do You Focus Cameras In The Field?

We have recently received a Siemens Star chart that we will use for manually focusing our cameras, and we are curious as to how our users focus cameras. So we ask: "What have you found to be a de-facto solution when focusing cameras during installation and/or maintenance?". Some of our inquiries include:

  • If a camera offers autofocus, do you have a subject or chart in the middle of the image to assist in focusing?
  • If you manually focus a camera, what do you do to gauge image clarity and sharpness?
  • If you use charts to focus or test image clarity, what kind do you use?
  • If a camera gets bumped out of focus switching from day to night mode, how do you refocus the camera?

We are curious to hear responses and feedback!


A box of CAT5e cable is a quick & easy chart. Just set it down at the point you want to focus, or set one near & another far. The labeling text provides as good a chart as anything else I've found. One trick for setting license-plate capture: At the drive or gate where you want to capture automobile traffic, set one box on each side of the passage far enough from the left/right curbs to represent the widest possible variation among incoming. This will provide a target in which to frame your shot and get as tight as possible (max pixels/foot at target distance) without missing plates on vehicles that come in off-center.