JEANNINE ALTON says How we are: Photographing Britain at London's Tate Britain is simply not to be missed

If your name's Joseph Nicéphore Niépce you're bound to make your mark. He did. He made, in 1826, the first photograph, and 150 of his umpteen followers from 1844 to 2006 have been assembled in the Tate's first blockbuster devoted entirely to photography.

The Linbury Galleries of Tate Britain are fairly bursting. There are, I'm told, 593 items - maybe more, counting the sequences of digitally-scanned images screened at various sites through the rooms.

All those statistics are important. This is a simply massive show. I made three circuits during my visit and it does demand careful viewing. Everyone will find something absorbing in those serried rows, and the reviewer can only cherry-pick and name-drop.

Curators Val Williams and Susan Bright adopt a chronological approach, and provide very good synopses for each artist - sorry, that's begged a big question already, but surely those two artificial' newcomers, film and photography, have sneaked in among the Muses and can be called arts by now.

It's in the first room we find the pioneers, Fox Talbot, Julia Margaret Cameron, Octavius Hill. Here too alongside Royal and Society portraits, and the tributes to lingering folk lore are the luckless - Barnardo boys, ragged schoolchildren and the insane, preserved in official archives in small, sad sepia rows. (It's worth noting the enormous range of private and public sources which have been drawn on to create the show.).

A major turning-point came with cheaper gear, mass production and the availability of artistic' material to the general public as never before. After all, not many people in the past could afford a great lump of Carrara marble or fine prepared canvas to record their views of the world and each other.

Here come family albums (Rothschilds, Sassoons, Vanessa Bell), picture postcards of holiday resorts, music hall favourites (Vesta Tilley, Dan Leno) carefully selected. I missed here the presence of the cigarette card series of dogs, racehorses, sportspeople and film stars so widely diffused, collected and swapped' at the time. Our own dear Oxbridge Ramsay and Muspratt and their begowned clientele are present.

A wonderful treat and something genuinely unique are the gold-tinted photographs of vegetables by Charles Jones (1905). Don't laugh, they are assuredly the product of love, and I found them irresistible. Of course, some may prefer Keith Vaughan's dishy lads (1939), The Daily Herald's huge library of TV and radio stars, David Bailey's Box of Pin-ups, the Magnum group of photojournalists, or Madame Yevonde's ravishing society beauties.

Less expected choices are Cecil Beaton's views of bombed London or Jane Bown's of Greenham Common, running against the grain of their standard work in fashion and portraits.

Beginning in the 1970s with Daniel Meadows's fascinating work in Manchester, many recent photographers specialise. Keith Arnatt makes abstract beauty from rubbish, Clive Landen finds it in 'roadkill'. Martin Power focuses on Essex, Peter Mitchell on Leeds, Paul Graham on the Great North Road (Little Chef, take a bow), Daniel Meadows on Manchester and Anna Fox in office life in her Workstations.

London remains a focus for many. Has it changed? Only superficially. The post-war section shows us the new immigrants, and later the vivid Notting Hill Carnival as well as the lingering Cockney traditions.

There are dreadful omissions in this scamper through the galleries. Actually, there are even a few omissions among the 593: sports and action shots, for example, are surprisingly rare in view of the national preoccupation with them. Non-photographic exhibits in display cases include W.G.Hoskins's epoch-making book The Making of the English Landscape - and could whoever borrowed my copy please return it NOW.

Joseph Nicéphore's discovery continues to proliferate astonishingly, in private and public life. Someone bought a disposable camera in Lloyds Pharmacy the other day while I was getting some aspirin, and we are threatened with ever more sophisticated CCTV that can capture car nameplates in four lanes of traffic at once.

Is photography a mass medium, or an art form, a document or an act of creation? It's hard to brood on topics like these when faced with such a varied cornucopia of new, familiar, remembered or forgotten images. Remember, however objective' they seem, they have gone through three filters - the photographers who took them, the curators who chose them and yours to view them.

You have till September 2 to see them at Tate Britain on the South Bank and the chance should not be missed. For details visit the www.tate.org.uk website.