Auto focus or manual focus: which projector suits how you use it?

What is the difference between manual, motorised and auto focus?

There are three ways a projector's lens is brought into focus, not two. You turn a wheel or ring by hand, you press buttons that drive a small motor, or a sensor measures the distance to the wall and the projector sets the lens itself.

Some makers call remote-button focusing manual. Dangbei, a projector maker, says of smart projectors: “You can generally adjust the focus by pressing the up and down buttons of the remote control until the picture is clear.” This guide calls that motorised, because a motor moves the lens.

Auto focus comes in two kinds. ViewSonic describes a time-of-flight (ToF) sensor as one that “measures distance based on the time it takes for photons to travel between the sensor’s emitter and the target area”, and contrasts it with “the normal auto focus that uses a camera for continuous image capturing and matching”. Other spec-sheet terms are defined in the projector glossary.

Which focusing method does each Neon+ projector list?

Neon+ publishes the focusing method on every product page, and its seven projectors cover all three approaches. The RM799 Q1 is the only one with a hand-turned scroll wheel; the V6 lists electric motor focus; the C2000 lists laser auto-focus; and the V8, X5 and X5 Plus list TOF laser focus.

Swipe sideways to see every column

Three lines need a question rather than a guess. The K5's TOF laser focus is marked “optional”, so ask Neon+ whether the unit you are buying has it.

“Electric motor focus” on the V6 names the motor, not the controls, so ask to be shown how it is adjusted. And the spec sheets say “laser auto-focus” for the C2000 but “TOF laser focus” for the V8, X5 and X5 Plus, so ask whether they differ and whether the C2000 refocuses by itself when moved.

The rest of each model's figures sit side by side in our guide to choosing a portable projector.

When is manual focus enough?

Manual focus is enough when the projector lives in one place: a tripod that stays in the same corner of a classroom, a shelf in a living room, a training room where the table never moves. You focus it once and it holds. As SSA, a projector maker, puts it, “once you set it, it stays—unless someone bumps the projector”.

Evetech, a South African retailer, frames the whole choice as “about setup frequency and control, not an automatic picture-quality winner”, and suggests a simple test: “Count the moves in a normal week before paying for convenience that may rarely be used.”

Set that one focus at the right moment. Epson's user guides say: “Wait 20 minutes after turning on the projector before setting the focus, zoom, and lens shift for maximum accuracy.” For a fixed classroom position, our guide to setting up a classroom projector covers the distance, aim and back-row check.

When is auto focus worth paying for?

Auto focus pays when the projector moves often: carried between classrooms, taken to a parent meeting or shared by several teachers who each set it up. Every move changes the distance to the wall, and ViewSonic describes the usual routine: “Traditionally, when a projector is moved, it needs to be refocused by either a press on the remote control to trigger auto focus, or manual adjustments on the focus ring.”

That is why focus and power go together. A battery model is built to be carried, and all three Neon+ projectors with a built-in battery, the C2000, K5 and V8, list a laser or TOF focusing method. Price is a weaker guide: the motor-focus V6 (RM3,800) costs more than the laser auto-focus C2000 (RM1,359), so let use decide. Our guide to battery or plug-in projectors weighs the two.

Treat speed claims as the makers' own. ViewSonic says ToF lets its M2e focus “in only one second, which is 3–5 times faster compared to current methods”, and Evetech quotes a rating of 0.1 seconds for a Wanbo model; neither is an independent measurement. ViewSonic's M2e also starts focusing by itself when moved, through a built-in motion sensor; ask Neon+ whether a model refocuses on its own or on a button press.

Auto focus also has limits. Evetech warns that “an uneven surface or extreme angle can still produce a result worth revisiting”, and SSA lists low contrast, such as dark scenes and plain walls, and reflective surfaces as cases it can struggle with.

How do you check that the focus is right?

Check focus the same way whichever method the projector uses: put up a page of small text and read it at the centre and in the corners, from the back row. If one side stays soft while the centre is sharp, Evetech says the projector may be off-axis or the surface may not be flat; straighten it, or try a smoother surface, before you refocus again.

1. Use small text. Evetech's rule: “Test small text at the centre and corners.”
2. Fix the angle before the focus. “If one side remains weak, change physical alignment before cycling focus repeatedly.”
3. Keep shape and sharpness apart. “Keystone concerns shape, while focus concerns detail, and those symptoms should not be mixed.”
4. Refocus after any change of distance. Moving the projector changes the image size as well as the focus. Neon+ publishes throw ratios of 1.4:1 on the Q1, 1.07:1 on the C2000 and 1.2:1 on the other five. Our guide to what a 1.2:1 throw ratio means works out the distance for your wall.

The classroom projector setup checklist puts these checks into the minute before a lesson, and our showroom visit checklist shows how to test focus on a model before you pay.