Pass ANVE Exam Guide

Focusing a camera with an auto iris is more accurate when set during lowlight conditions. In low light, the iris opens wider, resulting in a shorter depth of field. This forces the focus to be more precise within that narrower range, ensuring that the focus is set correctly. When lighting conditions improve and the iris closes down, the depth of field increases, maintaining a broader range of focus.

According to Johnson's criteria, the detection range for a person with an AXIS Q1921 with a 60 mm lens in clear weather is 1200 meters (3900 feet). This means that a human observer is able to detect a person at this distance with a 50% probability. Johnson's criteria is a widely accepted method for calculating the probability of detection, recognition, and identification of objects in surveillance imagery.

The AXIS Q60 Series cameras are designed to work with 60W PoE to ensure full functionality, including optimal pan and tilt speeds. If connected to a 30W PoE, the camera will still operate, but the pan and tilt functions will be limited in speed due to insufficient power. This limitation is outlined in Axis’s technical documentation for the Q60 Series, which specifies the power requirements and the impact on camera functionality when those requirements are not met.

The Axis pixel counter is a tool that allows users to verify that the camera's resolution meets the requirements for a specific scene. This is particularly useful in ensuring that critical areas are captured with sufficient detail for identification and analysis. The pixel counter helps in confirming that the pixel density is adequate for the intended surveillance purposes. Detailed explanations can be found in Axis Communications' camera setup and configuration documentation.