The gear that magically outputs light to form a beautiful images can be a complex piece of equipment to understand. Here are basics to help navigate the emerging types of projectors available on today's market.
LUKE MCELROY · September 7, 2017
4. Front or rear projection.
We don’t think about this, but rear projection is looking at light that’s coming at you. Front projection is looking at light that’s being reflected. Therefore, in a vacuum environment, rear projection will always appear brighter. But it always is affected by the other light contributors.
Lens Shift and Keystone
Lens shift is the ability to “shift” the image up, down, left or right. In 99.9 percent of projection, lens shifting does not affect the brightness or quality of an image coming out of a projector. However keystone is an entirely different issue. Have you ever had an image that looks like a trapezoid instead of a square?
That happens when the projector isn’t perpendicular to the screen surface. When your projection is off angle, the shape is no longer a square. Keystone correction is the process that turns the trapezoid into the correct aspect ratio and shape of your image. Most projectors include keystone correction, but keep in mind that this will degrade your quality and ultimately lower brightness in some capacity.
In the best situations to maximize brightness, avoid keystone at all cost by aligning the projector perfectly perpendicular to the screen surface. In addition, by doing the keystone and shifting inside the projector, it will not affect latency, which could result in delays such as seeing the pastor gesturing on the stage, only to see it moments later on the projection screens.
Finally, when looking at projection technology, consider the lens options, particularly these three types of lenses:
1. Ultra-short throw lenses.
These are almost like semispherical lenses that look like a bent sheet of glass or mirror to achieve ultra-wide angles from a projector.