Anyone floundering for a clue as to what the Turner prize is about should make straight for Disappearance at Sea by Tacita Dean, one of the four short-listed entrants in the Tate Gallery's competition show. There are various reasons for homing in on Dean's work, among them that it is the most painterly of this year's entries: something of an irony, given that it is actually a 16mm film. Her subject - inspired by the loss at sea of the yachtsman Donald Crowhurst - is probably the only one of the four that Turner would have recognised as being the sort of thing suitable for putting on canvas. That is not the prime reason for elbowing your way past Cathy de Monchaux's suede genitals, Sam Taylor-Wood's angst-ridden dinkies or Chris Ofili's Spandexed gangsta rappers to get to Disappearance at Sea, however. The point about Dean's oddly troubling film is that it is about lenses.
This can be said with some certainty because the artist is there, on video, to tell us so. Three lenses star in Disappearance at Sea: first, the revolving lens of the St Abb's Head lighthouse, its remorseless turnings hypnotically flattened by Dean's filming; then the optic through which the lighthouse is filmed, an anamorphic lens important enough to warrant its own credit in the show's accompanying catalogue. Perhaps the most significant lens in Dean's work, though, belongs to Channel 4, which will hand the artist a cheque for [pounds]20,000 (and film itself doing so) in the sadly unlikely event that she should win.
Describing the annual Turner prize junketings as a media event sounds like a truism, but Dean's game of mirrors suggests that it is true in another sense. One way or another, all four competing sets of work are shaped by their status as media products. Dean's second entry - Roaring Forties, a series of seven chalk drawings - is laid out like a film storyboard, the narratives of its various parts linked by instructions such as "pan into ...".
As well as using media-ish media, Taylor-Wood's photographic and video installations star media-esque people. …