Start from the room: multiply the throw ratio by the image width you want, and only consider machines that can sit where that puts them.
The arithmetic that comes first
Throw ratio × image width = the distance the projector needs. A ratio of 1.5 and a two-metre image means three metres of distance. If the sofa is at 3.2 m and the ceiling mount would be behind it, that machine is out regardless of its specification — and no amount of keystone correction buys back a metre.
The second decision: where the light goes
Real optical lens shift moves the image without distorting it. Digital keystone squares the image by throwing away pixels and softening the result. A projector with vertical lens shift can sit on a shelf; one without has to sit in line with the screen.
The third: how bright, for that image, in that room
See the room, the size and the ambient light as one question rather than three. A machine that is right for a dark room at two metres is a different job from one that has to work at dusk at three.
What to spend on last
Resolution. It is the specification most prominently advertised and the one that changes least at ordinary viewing distances. Light, contrast and placement change the picture first.
Questions people actually ask
Is 4K worth it on a first projector?
On a two-metre image watched from three to four metres, the difference between native 4K and a good 1080p machine is smaller than the difference brightness and contrast make. At the same price, a 1080p projector generally puts more light and more contrast on the wall.
How much should I set aside for the screen?
Enough that it is not an afterthought. A flat, correctly sized surface with a black border is the cheapest visible improvement in the whole system, and an ultra short throw machine specifically requires a screen built for it.
Last reviewed 4 September 2026