BLOCKBUSTER shows are all very well for big retrospectives, but small exhibitions can be just as rewarding, and certainly easier on the feet. Such is the case at the Watts Gallery, whose latest exhibition explores, by means of some 40 exhibits, the part played by early photography in the work of John Ruskin.

Their main galleries devoted to the oeuvre of G. F. Watts, and with limited additional gallery space, the Watts Gallery curates punchy exhibitions to resonate with its permanent collection while illuminating lesser-known corners of Victorian art.

The champion of Turner, the scourge of Whistler, and the leading art commentator in the 19th century, Ruskin was a contemporaryof Watts and an accomplished draughtsman. For him, drawing was a compulsion, which fed into his credo that close observation was essential for understanding: he wrote in 1852: "There is a strong instinct in me, which I cannot analyse, to draw and describe the things I love."

Drawings were a means to an end, simple records of what Ruskin saw before him, and often left unfinished once he had captured what he needed. They were also useful aide-memoires for his literaryworks such as The Seven Lamps of Architecture (1849) and The Stones of Venice (1851-53). Steeped in the traditional art of watercolour, Ruskin was, however, an enthusiastic early adopter of the daguerreotype, a photographic process invented in 1839.

Fragile one-off images, formed on silver-coated copper plate, daguerreotypes were popularly used for portraiture; but it was their abilityto record accurately inanimate architectural detail and majestic landscape which attracted Ruskin. By 1849, he had bought a camera and trained his manservant in its use. Throughout the 1840s and'50s Ruskin acquired, commissioned, or made some 325 daguerreotypes.

"John Ruskin: Photographer and Draughtsman"selects 20 of these diminutive images - rarely displayed because of their frailty - and sets each one alongside a drawing of a comparable subject. By dividing the exhibition into four geographic sections, viewers follow "the passion of Ruskin's eye" as he travels around his favourite European haunts: Venice and Verona, Tuscany, Northern France, and Switzerland.

It is instructive to see where Ruskin's eye alights. A fine daguerreotype of late 14th-century tracery on Rouen Cathedral exemplifies what was for Ruskin a pivotal moment in Gothic architecture.In Lucca, the tomb of Ilaria del Caretto, carved by Jacopo della Quercia, fulfils Ruskin's "ideal of Christian sculpture". In Verona, the Castelbarco Tomb, perched above a gateway adjoining the Church of Santa Anastasia, impresses Ruskin as "the most perfect Gothic sepulchral monument in the world", but, while the daguerreotype supplies the down-to-earth detail, it is Ruskin's watercolour that captures the tomb's elegiac atmosphere.

Ruskin appreciated that photography could record for posterity architecture that might fall prey to developers or "restorers", but hewas not slavish in his devotion, believing that drawing could capture nuances of light and texture which photography could not. By the 1860s, Ruskin had spurned photography, but his infatuation with it for two decades provides the basisof a succinct but satisfying exhibition.

"John Ruskin: Photographer and Draughtsman" is at Watts Gallery, Down Lane, Compton, Surrey, until 1 June. Phone 01483 810235.

www.wattsgallery.org.uk