STEP 4:
setting up the lens #2

Now using the remote control, press and hold the button ‘IN’ until the prisms stop again.

In order to match the screen width, the fine tuning of horizontal expansion can be accomplished by adjusting the cap screws inside the lens. The tuning is done with the cap screws to where the prisms stop after switching the lens to ‘IN’ position (marked with red circles in the picture). Opening the screws release the prisms to rotate further, thus allowing the picture to expand more from both sides. While closing the screws make the sides less wide.

When the both sides of the picture matches the screen edges, the correct position has been found. Depending on the throw ratio of the system, the picture geometry has now some amount of pincushion distortion. The distortion can be faded out by a slight picture over scan to the velvet frames or by the use curved screen. Some projectors also have the electrical pincushion correction settings. In order to obtain the distortion even for both upper and lower parts of the picture, the optimum tilting angle has to be found in the lens settings.