DVR Security Forum

TCM-5311 is a versatile camera. To provide perfect focus with different lenses, it has a feature called back focus adjustment. Back focus slides the sensor array forward and back, in effect shifting the target focal plane.

Here's how to adjust back-focus for ACTi TCM-5311. We use LEN-207 as an example, but this procedure works on all lenses.

First we would adjust the lens, and set zoom to widest view, and focus to nearest. There should be no focus on screen.

1. Connect TCM-5311 to a computer via ethernet cable. If PoE switch is available, then there's no need to connect to external power adaptor. Login to Web Configurator and display live video. If DC-Iris enabled Lens is used, remember to connect the Iris control cable.
2. Set Zoom to Widest and Focus to Nearest.
3. Turn Back Focus control knob counter-clockwise all the way to the end. (facing the same direction as the camera).
4. Point the camera at an object 75 cm away (2.5 feet).
5. Slowly turn the knob clockwise, until the object shows in clear focus on screen. This means that the camera can attain focus at the widest zoom angle of the lens.
   [*Shift focus to infinity. Shift the zoom slowly from wide to telephoto. During this process, the image on screen will gradually come into focus, yet it will not achieve perfect focus, and will become blurred again. This is “RIGHT”, and is the condition that we want. Do not worry.
6. Point the camera at an object 4.5 m (or 15 feet) away. Shift the focus slowly towards the near side. When you get good focus on the object, this means now we also have good focus on the telephoto end of the zoom range.
7. Next we verify the focus by shifting the zoom to widest, and adjust focus to near a bit. When we attain focus here, we should have a very good depth of view, and the camera can support the full zoom range of the lens attached.

Video Clip for backfocus instruction
http://actiftp.hosting4less.com/ACTIGENE...uction.mpg