Wolfgang Tillman's new show is a world of differences: bodies and buildings, trays of eggs and vernacular Tunisian houses, pictures of the world and pictures of nothing. There are on-the-hoof shots and darkroom experiments; large photographs and small; intimacies and distances. There is a photograph of a young man's ear, caught by the clippers while having his hair cut; there is a shot of a forest in Tierra del Fuego, the trees blitzed by light and shade.

All this might be bewildering: the jumps in scale, the sheer variety of Tillmans's subject matter, his different means of presentation (huge sheets of photographic paper hung from bulldog clips, other things taped directly on to the wall, work sitting in Perspex boxes). But it is all orchestrated with a sense of rhythm, pace and surprise.

For Tillmans, photography can be a record, something observed or something never seen before. It can also be painting by other means: pinkish fields with sudden judderings that recall skin seen close up; strange abstractions generated by the random dirt on the silver drum of Tillmans's printer (and which recall the squeegeed abstractions of Gerhard Richter, whose art is also much concerned with the relationship between painting and photography, intention and meaninglessness). Some of his photographs are near-monochromes, recalling thin shadows crossing the walls in a pale room, or the acid lighting on a highway at night. Sometimes it is hard not to think of paintings by Ellsworth Kelly or Raoul de Keyser.

Here is a still life, an accumulation of little objects on a window sill: a conker, an acorn, a key, some lenses, a number of stainless steel sex toys for stretching your balls. (At least that's what I thought they were. When I asked him, Tillmans called me a pervert. He was right.) Elsewhere, there is a small image of a naked man on his knees. He might be praying. Weirdly, it looks more like a pallid ink drawing or a water-colour than a photograph. In fact, it is a faded fax, a degenerated thermal image of a photograph now fixed for ever on the verge of disappearance.

Somehow everything makes a kind of sense. The cumulative effect of Tillmans's art may be puzzling, but it isn't a puzzle. Its logic lies in process rather than in the production of telling images. The differences in his work are themselves the point: from his coloured rectangles dancing on the Serpentine gallery's white walls (they make your eyes dance, too) to the wonky, knocked-together tables that stand in the middle of one room, laden with cargoes of text, newspaper pages, printed ephemera. Here is an article on religion by Polly Toynbee, commissioned by Tillmans for an edition of Die Zeit he guest-edited; there is a piteous image of two young men – little more than boys – about to be hanged in public for the crime of homosexuality in Iran; here is an article by Tillmans himself, a keen amateur astronomer, on the 2004 transit of Venus. What is the carpet tile doing among all this stuff, on one of the tables, a blank square of pixellated industrial flooring?

If art can talk about the world, the big question is where to stop. What do you include and what do you exclude? Sometimes, and especially in photography shows, you can end up going from one damn thing to another, driven by the hope of finding something salacious, erotic or just plain peculiar. Tillmans does his best to call a halt to such aimless gawping by constantly giving us things that need to be approached and looked at in different ways – as images, as constellations of pictures, as objects.

For some artists, doing one thing well is enough. But photography – perhaps more so than painting – allows for many different kinds of incidents and singularities. The great pleasure of this exhibition is its orchestration of different registers and voices. The last big Tillmans show I saw, in Berlin in 2008, was called Lighter. Walking through it, I felt heavier and heavier: it was so full of stuff, it was hard to hold the logic of it all in one's head. Retrospectives often fall into this trap. The smallness of the Serpentine gallery demands much tighter editing; the space edits the work as much as the artist.

Tillmans's show was hung and finished two days ago, but late on Tuesday night the artist decided to rearrange part of the hang. Things aren't right until they're right, and rightness seems to be a big issue for the artist. The big problem, of course, is what happens when the crowds pour in. You lose all those perfect sightlines.

The extreme variety of Tillmans's work, with its different printing techniques and technologies, makes for a fascinating show on many levels. There are luscious photographs and dirty faxes, photocopies that accentuate the dismal Edinburgh light and glossy prints that bring out the unpleasant glamour of Shanghai by night; there is a vivid cyan blue invented in the darkroom and too artificial to be the sky. It is all here. These could, of course, all be exercises in style: I can do this, and this, and this; you can have it this way or that. You want abstract? I can do abstract. You want gritty, or sexy? Well, here they are. But there is more to Tillmans's work than formal intelligence. He wants it all, and why not?

Andrea Spotorno

Occasionally, when he was much younger, the celebrated American photographer William Eggleston used to turn off the lights at his home in Memphis, Tennessee and shoot guns in the dark for fun. "The house was riddled with holes made by $6,000 antique shotguns," an acquaintance once revealed. He is often described by journalists as a heavy-drinking hellraiser, with a weakness for Savile Row suits and expensive cars – over the years, he has owned a Ferrari, a Jaguar, a Bentley and a Rolls-Royce.

True to form, after a long lunch with the German fashion photographer Juergen Teller, Eggleston turns up late for our interview in the Fondation Cartier, a museum in Paris devoted to contemporary art, where a new series of his photographs has just opened. A few months short of his 70th birthday, he is dressed immaculately in a navy suit, his brown brogues buffed to a shine – yet there is a whiff of something decidedly louche about him. He slumps in a leather sofa that has been placed in the foyer to his exhibition, not far from a baby grand (Eggleston is an accomplished pianist, and a devotee of Bach). A solitary pearl of perspiration rolls down his forehead.

During this period, he amassed thousands of pictures, from which the foundation's director, Hervé Chandès, selected 70 for the show. As Eggleston tells me, with some effort, as though dredging up the words from the depths of his soul, "I'm not particular. I don't have favourite pictures." He pauses, before continuing: "To me, the whole project, no matter what size, is the work."

Born into a wealthy Southern family (he has never needed to earn money), and raised on a former cotton plantation, Eggleston is credited as a pioneer of colour photography. His breakthrough exhibition at the Museum of Modern Art in New York in 1976 showed that colour photography could be an artistic, and not merely a commercial, medium. At first, the critics condemned his seemingly casual snapshots of everyday life in the Deep South as "perfectly banal". But the book that accompanied the exhibition, William Eggleston's Guide, proved extremely influential. His free-and-easy images, shot quickly without a tripod from quirky angles, glow with gorgeous colour. They were soon seen as refreshingly democratic in both form and content, a tonic to the stagy, studio-manipulated fine-art photography, which, before 1976, had generally been black and white. "I had this notion of what I called a democratic way of looking around," Eggleston once said, "that nothing was more important or less important."

The new Parisian pictures continue in this vein. With typical perversity, Eggleston refuses to frame a picture that might result in a visual cliché. There are no shots of famous monuments, no pictures of wrought-iron signs for the Métro. Photographs of chic Parisians strolling through the Jardin du Luxembourg are nowhere to be seen.

Instead, there are images of packing crates and graffiti, of a woman begging outside the entrance to the Bastille Métro station, of neon-green light reflected in a puddle of rainwater on a dingy street corner, and of cheap shops selling gaudy tat. Eggleston is drawn to the city's neglected nooks, and often shoots close-up so that it is not immediately clear what the subject of a particular picture is. In fact, many of his photographs could have been taken in any city in the world. Somehow I doubt that they will be used by the Parisian Office du Tourisme any time soon.

Was he consciously trying to avoid clichés? "Not really," he says in his slow, gravelly baritone. But surely he was aware of the masters of photography who documented Paris during the 20th century – people like Eugène Atget and Henri Cartier-Bresson? "I knew about them," he says. "That was in the back of my mind." Yet, as he explains in the exhibition guide, he approached Paris as if it was just anywhere: "That resulted in pictures infused with a little mystery. You're not quite sure: is this Paris, Mexico City, elsewhere? I didn't change my style for Paris. I just did as always, used the same approach."

Eggleston's photographs of Paris will not be to everyone's taste. At first glance, they seem nondescript. But I love the fact that they are worlds apart from the familiar iconography of this famous city. Eggleston's aesthetic is wonky, half-cocked, provisional – and energetic. His pictures feel fresh and true: tiny scraps of reality ripped from the everyday fabric of life in a modern metropolis. He is capable of transforming the trivial into the transcendental, of wresting beauty from unexpected and overlooked places.

His new photographs are also eminently formal, almost abstract. In many of them, bold splashes of colour divide the image into sections, like a vibrant geometric painting by one of the Suprematists. Eggleston only ever takes a picture of something once, which means that his grasp of composition is all the more phenomenal because he never poses his images. His sense of colour would turn most artists, well, green with envy.

"Everything must work in concert," he says. "Composition is important but so are many other things, from content to the way colours work with or against each other."

Alongside his series of Parisian photographs, Eggleston is also showing 40 abstract paintings and drawings for the first time – colourful squiggles that were mostly created using felt-tip pens. He has drawn like this since he was a child (he didn't become interested in photography until he was at the University of Mississippi, where he became captivated by the work of Cartier-Bresson), and these pictures owe a clear debt to Kandinsky, one of Eggleston's favourite artists. They also feel exceptionally musical, brimming with rhythmic swirls.

"I like that idea," he tells me, "though I don't think about that consciously. I like to think that my works flow like music. That may be one reason I work in large groups versus one picture of one thing, it's the flow of the whole series that counts. I think when Paris is finished, it will flow."

As things stand, the project is far from finished. "Even though I now have several thousand pictures [of Paris], I still feel I have just barely begun," he says. "It's a big project. I hope it will be my crowning achievement." But, when pressed on what else he plans to document, he clams up. "I don't have anything in mind," he says. "Nothing more I can say would make any sense yet, because the series is not finished. I'm interested in wherever I go." He pauses. "There's no shortage of visually interesting places to me."

It's clear that Eggleston hates talking about his work. Throughout the interview, he is courteous but also reticent, like a well-dressed screen idol who never uses three words when one will do. He is also keen to avoid discussing the meaning of his work, and refuses to talk about individual images. His silence piques my curiosity. Why does he hate to talk about his photographs? "I don't know how to," he says, as if it's the most obvious thing in the world. "I'm not busy talking, and I don't write – because I'm busy making images."

Alastair Sooke

Tom Sandberg
Inge Morath
Alasdair McLellan

Elad Lassry

Bernard Plossu
Back. After a month in Lebanon, Turkey and Syria. Above is Ara Güler. The Eye of Istanbul.