Francesca Woodman killed herself at the age of 22, the biographical fact that colours her work and which it is de riguer to mention. She left behind paintings, it is said, as yet publicly unseen, and literally hundreds upon hundreds of negatives and 800 proofs of black and white pre-digital photography. And since that very early death – and early death, whether suicide, accident, disease or murder has been sometimes seen with rabid cynicism as an outstanding career move – she has, over the past two decades, become something of a cult figure.

There’s war in the world outside and much conflict at home in Norwegian director Eric Poppe’s A Thousand Times Good Night. The film is centred in every sense around the poised, taut performance of Juliette Binoche as war photographer Rebecca, whom we first encounter at work in Afghanistan, as she follows the detailed preparations of a female suicide-bomber being prepared for martyrdom.

If events in the Middle East, the prospect of the school run or the onset of autumn are conspiring to lower your spirits, then escape to the V&A and immerse yourself in the dreamy elegance of Horst P. Horst’s magical fashion photographs spanning a career that lasted 60 years.

What makes an exciting “genuine” photographer is fairly simple: what do you see in the photographs? Do they compel you to look at them? How evocative are the images? How interesting are the compositions? These are among the criteria which separate the merely good from the truly great – and who would have expected that there are truly great photographers yet undiscovered, or even some that didn’t want to be discovered? This is the backstory of Finding Vivian Maier, an exceptional and exceptionally compelling documentary co-directed by John Maloof and Charlie Siskel.

From Apocalypse Now to Blue Velvet to Speed, as a screen presence Dennis Hopper grew ever more scary. Lately gallery-goers have got to know another side of Hopper via his painting. Now there is a belated run-out for his work as a photographer, although work is maybe the wrong word. He spent much of the Sixties with a camera slung round his neck, but didn’t make a dime from any of his pictures. “They cost me money,” he said, “but kept me alive.” Hopper rode out of the decade on a Harley as director of Easy Rider and he didn’t pick up a camera again.

John Deakin was lukewarm about his career as a photographer because his heart wasn’t in it. Really, he wanted to be a painter, and so it was in spite of himself that he became a staff photographer at Vogue in 1947, acquiring a reputation for innovative portraiture and fashion work. Vogue’s studio was dangerously close to Soho and Deakin was prey to its temptations, his alcoholism and dubious friendships with many of its most celebrated and notorious characters providing a constant distraction.

Not so long ago, photographers were rejoicing in the freedom the digital revolution seemed to bring; unencumbered by the limitations of film, paper and darkroom practice, photography was suddenly liberated from the niggling pedantry of material constraints.

Several hundred photographs, of varying scales and most of them newly printed gelatin silver prints in superb tones of greys blacks and whites, take us into a world that has been subliminally familiar to us for nearly 50 years.

In 1997 I was in South Africa working on Truth and Lies, my book about the Truth and Reconciliation Commission, when the New York Times Magazine said that they were doing a major feature on Mandela. He’d been in office for three years. The photographs were taken in the presidential house, the former seat of the oppressors. It felt very surreal for me because even the décor was Cape Dutch furniture. It was not what you might imagine for a black president.

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.