The precise nature of the photographic portrait has always been contested, and this year’s Taylor Wessing Prize only fuels the debate. While historically photographers have questioned the portrait’s ability to go beyond physical fact to reveal a subject’s character, this exhibition of shortlisted entries challenges the notion that a portrait should tell us about its subject at all, while also raising questions about the ethics of picture-taking.

At the beginning of the 17^th century an anonymous Anglo-Netherlandish artist produced an elaborate procession portrait of the septuagenarian Virgin Queen, tactfully portrayed as though several decades younger, when she had succeeded to the throne in her mid-twenties. Elizabeth I is  held aloft under an embroidered canopy and surrounded by Knights of the Garter, courtiers, members of the royal household, and aristocrats.

Grayson Perry is sitting pretty amid a swathe of soft-focus pink. Dressed as his alter ego Claire he sits on a pink bed with pink pillows, his pink ruched dress spread about him with its frilly underskirt on view. Placed on his lap are his thickly veined, restless hands, fingers knotted, and he stares out at us from this frosted-pink confection of a canvas wearing a look that might be described as both winsome and quietly content.

Laura Knight’s wartime masterpiece Ruby Loftus Screwing a Breech-Ring (1943) is a subtly glamorous picture, strikingly composed. A frieze of blue-clad women at an armament factory workbench are in the background, highlighting the profiled figure of Ruby tending her elaborately complex machine, at an oblique angle to the picture plane. Unashamedly a celebration of a positive triumph over inescapable necessity, the image emphasises achievement, and doesn’t indicate the inescapable monotony, noise and general rough hub-bub of the working conditions.

One is increasingly struck by the oddity of an annual portrait prize, or at least I am. Imagine an annual still life award or an open competition for a major prize for abstract art. And imagine how formulaic and stale that would soon become. How many variations of a photorealist table laden with grapes or half drunk glasses of wine could you put up with? Or just think of all those coolly two-tone geometric canvases that’ll come pouring in.

“I don’t like the family Stein; There is Gert, there is Ep and there’s Ein; Gert’s Poems are bunk, Ep’s statues are punk, And nobody understands Ein” (Anon).

Jacob Epstein (1880-1959) did indeed sculpt Albert Einstein when the physicist was briefly interned in London on his way to America in 1933; Epstein’s bust of the quizzical shock haired scientist is currently on view at the Victoria and Albert. Epstein described his subject, already legendary, as humane, humorous and profound and was particularly struck by his hair going every which way.  

Scores of reddish-bronze skinned men, and a few women and children, in full regalia, festooned in face paint, feathers, jewellery and decorations of all kind. They stare out at us, impassive and imperturbable, immortalised by George Catlin (1796-1872), the most famous American artist you have never heard of. 

Travelling through Canada by train – more decades ago than I care to divulge here – I bought a book of Man Ray photographs at Banff in the heart of the Rockies. I spent the rest of the journey with one eye on the majestic mountains, and the other glued to the luminous, edgy, ineffably stylish images of the American surrealist in Paris.

The first thing to say about Paul Elmsley’s portrait of the Duchess of Cambridge, which was unveiled yesterday at the National Portrait Gallery, is that it looks rather better in real life than it does in reproduction. That doesn’t make it a great painting, but nor is it a risible one. The soft-focused, Vaseline-smeared visage, framed by that undulating cascade of buoyant hair (it’s unfortunate how much this makes her look as if she's taking part in an ad campaign for shampoo) is more convincingly defined and skilfully modelled than it is when you see it on the screen.

The Taylor Wessing Photographic… well, you get the drift. It's quite a long title for what is now one of the most fascinating and wide-ranging exhibitions of photographs mounted in London, and which goes out on tour nationally next year. It is described as a snapshot of contemporary portrait photography, and this is one of the strongest iterations yet, 60 photographs selected from an international submission of over 5,000 images from more than 2,000 photographers, all taken within the last year or so.