When choosing a projector, we’ll notice in the specs there are variable focus and fixed focus. What’s the difference between them on earth?

The most notable distinction between them is that if you place both of the two types of projectors in the same position, fixed focus projector can zoom in through lens adjustment, while variable focus projector cannot zoom in through lens adjustment.

The difference between variable focus projector and fixed focus projector

  • Variable focus projector

Variable focus technology realizes the effect of zooming in/out through moving the inner lenses to change the position of focus as well as the focal length, meanwhile adjust the field of view. To put it simply, variable focus is able to zoom in and out by adjusting zoom ring inside the projector.

  • Fixed focus projector

Technically speaking, fixed focus is incapable of zooming in or out. Because the lenses are fixed inside the unit. However, projector with fixed focus can emulate the process of zooming through algorithm and create the effect of zooming similar to variable focus, except that there would be a certain amount of resolution decrease.

Comparison between fixed focus and variable focus

Fixed focus projectorVariable focus projector
Lenses fixed, allows no zoom technically
Compact size
Lower costs
Image quality affected by digital zoom  
Zoom freely by adjusting lenses
Larger in size
Higher costs
Keep fidelity to image while zooming  

More things you need to know

When you use a fixed focus projector, it’s better to place it in the right throw ratio so that the projector won’t activate the function of digital zoom. In this case, you’ll get the projected image as sharp and original as possible.

However, a variable focus projectors are more flexible, since you can adjust the lenses to get the most accurate image regardless of where you place it. Hence, what we will see is, placed in the same position, variable focus projectors can provide larger image output on screen than fixed focus projectors do.