Drama along the line of sight

TIL one reason some of us are so dejected and furious at the TV when in, a cricket match being telecast live, a fielder appears to miss catching the ball even though it looks like he easily could have. A.k.a. why my grandpa loses his shit when M.S. Dhoni won’t chase a ball that has spun past his gloves and is racing towards the boundary. (If you don’t follow cricket, here’s a primer.)

When the bowler runs up to the wicket to bowl a ball, the camera focuses on the batsman, but the frame is set to capture everything from the umpire’s position in the foreground to the back-most man on the slip cordon (the line of fielders standing adjacent to the wicketkeeper) in the background.

Screen Shot 2017-10-10 at 17.58.42

However, the camera that’s recording this is located far from the pitch itself, down the ground and beyond the boundary line, at least 270-300 feet from the batsman (according to Law 19.1 of ICC Test Match Playing Conditions). This results in an effect called foreshortening. When the camera has a long line of sight, distances along the line of slight are shrunk by more than distances across the line of sight. For example, in the screenshot above, the pitch is 66 feet long and the wicketkeeper is standing almost 26 feet behind the batsman.

However, onscreen, the ball to be bowled is going to appear as if it’s going to travel 20 or so feet to the batsman and the 10 or so feet to the wicketkeeper. On a cognitive level, viewers are also unmindful of the foreshortening for two reasons: they used to it, and because the ball bowled (by Bhuvaneshwar Kumar, above) is going to move at 120-140 km/hr.

At the same time, foreshortening is going to make it appear as if it’s moving at a slower speed. Broadcasting channels employ on-ground radar to track the speed of the ball and display the number almost immediately after it’s bowled, so foreshortening could arguably dull our sense of how high these speeds are as well.

However, the contrast between shortening along the line of sight versus across the line of sight isn’t very evident in a cricket broadcast because the distances are of comparable magnitudes. Instead, consider the Cassini probe shot of the Jovian moons Epimetheus (lower left) and Janus shown below. Without accounting for foreshortening, it would appear as if the moons are close to each other. However, at the time this image was taken, Janus, on the right, was 40,000 km behind Epimetheus.

Credit: NASA/JPL/Space Science Institute
Credit: NASA/JPL/Space Science Institute

In the same vein, foreshortening is a common confounding factor when natural terrain is scanned from space.

Axiomatically, painters and graphic artists use foreshortening to imply depth in the viewer’s eye and also suggest an ‘appropriate’ viewing angle. Frescoes created in the 15th century were among the first to use foreshortening to provide an illusion of depth on two-dimensional surfaces. A famous example is Andrea Mantegna’s Lamentation of Christ, created c. 1480. Thanks to the effect being in play, Jesus’s body is angled towards the viewer (along the line of slight), drawing attention to this chest, abdomen, genitals and the holes in his hands and feet.

Credit: Wikimedia Commons

Finally, foreshortening is held to be an essential compositional feature of millennials’ most ubiquitous creation: the selfies. The American art critic Jerry Saltz wrote for Vulture magazine in January 2014,

Maybe the first significant twentieth-century pre-selfie is M.C. Escher’s 1935 lithograph Hand With Reflecting Sphere. Its strange compositional structure is dominated by the artist’s distorted face, reflected in a convex mirror held in his hand and showing his weirdly foreshortened arm. It echoes the closeness, shallow depth, and odd cropping of modern selfies. In another image, which might be called an allegory of a selfie, Escher rendered a hand drawing another hand drawing the first hand. It almost says, “What comes first, the self or the selfie?” My favorite proto-selfie is Parmigianino’s 1523–24 Self-Portrait in a Convex Mirror, seen on the title page of this story. All the attributes of the selfie are here: the subject’s face from a bizarre angle, the elongated arm, foreshortening, compositional distortion, the close-in intimacy. As the poet John Ashbery wrote of this painting (and seemingly all good selfies), “the right hand / Bigger than the head, thrust at the viewer / And swerving easily away, as though to protect what it advertises.”