The Iris of a camera is actually the same concept as the Iris of a camera or phone. It allows light from an object to pass through the lens and enter the camera, forming an image on the sensor so that we can see the captured image. The function of the Iris is to determine the amount of light entering the camera, similar to the width of a water pipe. A larger Iris (with a smaller F-number) allows more light to enter. The F-number is opposite to the size of the Iris with a smaller number indicating a larger Iris and more light.
For users who have frequent nighttime shooting needs, they may consider choosing a camera with a large Iris (small F-number) and infrared night vision function. For home cameras, an Iris of F/2.0 can meet outdoor monitoring needs and provide a clear captured image.
Note: A smaller Iris results in a darker image with better depth of field; while a larger Iris results in a brighter image with poorer depth of field. Therefore, for black-light cameras, in order to improve imaging performance at night, they may use an F/0.9 or F/1.0 Iris lens, but the image focus travel is short and it is easy to cause the image to be out of focus and unclear. While ordinary web cameras usually use an F/2.0 or F/1.8 lens, with longer focus travel and clearer images. Therefore, it is not always better to have a larger Iris; both factors need to be considered.
