modified on 18 November 2009 at 17:47 ••• 2,560 views

Camera Focus Adjustment

From CAG

Jump to: navigation, search

We use small color cameras that also have the ability to display low-light images using infra-red LED's. These cameras are moderately priced and very reliable. Our cameras are manufactured by Q-See, and are readily available at popular electronics stores.

Alt=Color/IR camera out of the box

We have found that the 6mm lens is adequate for the deep portion of a nest box. For closer views such as those in the boot section of the nest box, in a cage, or in the brooder require the wide-angle 3mm lens. The only issue is the cameras are intended for outdoor applications where objects are farther away than we experience in aviary. This requires a simple adjustment to the camera - something that will obviously void your warranty. The process outlined below adjusts the focus of the lens so that closer objects will appear sharp in the image.

Adjusting the Camera Focus The first step is to unplug all cables on the camera. To start the disassembly, unscrew the two parts of the cast housing. They are simply threaded with an O-ring for water tightness. The split is usually central to the housing, and has a label spanning the split which should be cut. Grabbing both halves of the housing, unscrew using normal "lefty-loosey" twisting. The front housing will come off, revealing the internal workings of the cam.

Alt=Color/IR camera partially disassembled

Internally, there are two assemblies that we are concerned with. The first is the circuit board containing a ring of infrared LED's. They emit an infrared light that we cannot see, but the camera sensor can. The other part, located behind the LED baord, is the camera control board which contains the camera sensor and lens components.

With the front housing removed, the ring of LED's is easy to see, as well as the lens - the black circular piece in the center of the LED's. Between the lens and the LED board is a small foam ring that is easily pulled out.

Hold onto the LED section and carefully remove the electronics from the housing, taking care to not pull beyond the reach of the wires. Additional wire can be fed into the housing by unscrewing the strain relief and pushing more wire into the housing.

Alt=Color/IR lens and control board

Once removed from the housing, there are small screws holding the LED board to the camera control board. Remove the screws to gain access to the lens. Once removed, you will note a cap-like assembly over a threaded tube. This is the actual lens. The lens is screwed in and out on the threaded tube to adjust the focus. However, there is a set screw holding the ring securely to the tube. Using a jeweler's philips-head screwdriver, carefully remove the set screw. The ring will now easily move on the tube, allowing focal-length adjustment which will come later.

Next, we need to reassemble part of the camera so that we can adjust the lens to the desired focal length. Reassemble the LED board to the camera control board, securing the screws that holds the assembly together. Carefully place the electronics back in the rear housing (do not put on the front housing yet).

We need to know how far the camera will be from the desired viewing object. For example, measure the distance of the nest box tall section, subtracting a couple inches for the nestbox material. We will now place the camera on a table, and place a test object the same distance as that measured earlier. This will allow easy adjustment of the focus.

Connect the camera to the video viewing source and insure there is an active image of the test object. Carefully screw the lens in and out of the tube, watching for which direction provides an improvement in focus. Once adjusted to the proper focal length, disconnect the camera cables insuring power is off.

We leave the lens ring set screw off the lens so that we can make easy adjustments later on. However, if you want to fix the lens at the current setting, disassemble as before and reinstall the set screw.

Screw on the front housing onto the rear housing to complete reassembly. Mount the camera and reconnect all cables to check for proper operation. Enjoy your sharp video images!