Apparition, Queen Elizabeth Hall, London

The dancer Desirée Kongerod walks on stage and taps the gauze backdrop. The surface lights up under her hand; a bright line spreading across the gauze to meet Rob Tannion on the far side of the stage.

The dancer Desirée Kongerod walks on stage and taps the gauze backdrop. The surface lights up under her hand; a bright line spreading across the gauze to meet Rob Tannion on the far side of the stage.

Apparition is a digital dance by Klaus Obermaier, though the choreography is by the dancers. Abstract patterns shimmer on the backdrop and on the dancers' bodies. Sometimes Tannion and Kongerod dance in delicate half-light as the screen goes wild behind them; sometimes, as in that opening, the projections respond to the bodies.

It's an episodic piece. With weaker sections, Apparition loses pace. Obermaier can be merely clever, repeating ideas or overwhelming the dance with his designs. But Apparition's best digital imagery is built into the dancing; not just draped around its edges. Physical and virtual movement merge. That first line between the dancers follows their movement, as if it were a physical cord. One end dips as Kongerod falls to the floor; the other rises as Tannion lifts his arms. More lines flow across the backdrop, waving like reeds in the wind.

Then there are pinstripes. Narrow lines are projected on to the screen and the dancers. It turns them into camouflaged figures until their body lines tilt; horizontal against a vertical landscape. Obermaier's backdrops keep moving: the pinstripe lines spread out and come closer together. As with Bridget Riley's paintings, those wide and narrow stripes give an illusion of depth. The flat screen seems to bulge and writhe, with dancers vanishing and reappearing in front of it. Dots become lines, shooting stars, then converge on a dark space. The sense of motion is dizzying.

In another scene, the dancers stand in half-darkness; silhouettes against grey light. More stripes appear on their bodies, but these are words broken up by movement. As Tannion and Kongerod dance, the letters spread out to the sides, giving them halos.

Pure dance moments give the eye some relief from the whirling images. Kongerod and Tannion are strong, athletic dancers. In one duet, they echo each other - as he throws his leg up for a handstand, she kicks high beside him. Clinches are pragmatic; not emotional: they clamber over each other. At one point, Tannion stands bent double as Kongerod mountaineers up him; standing on his hips, gazing ahead.

The dancers can't always hold their own against the digital storm. Sometimes it changes how we see them; sometimes it blanks them out. They keep disappearing, on screen as well as off it. Obermaier projects photographs on to his backdrop; the image already broken up into squares. As Tannion taps his own face, it breaks up - the squares pouring back and forth. You can hardly see the real body for the heaving, weaving screen.