Answer by taking a quote from the following article:

Charles Lutwidge Dodgson (; 27 January 1832 - 14 January 1898), better known by his pen name Lewis Carroll, was an English writer, mathematician, logician, Anglican deacon, and photographer. His most famous writings are Alice's Adventures in Wonderland, its sequel Through the Looking-Glass, which includes the poem "Jabberwocky", and the poem The Hunting of the Snark - all examples of the genre of literary nonsense.

In 1856, Dodgson took up the new art form of photography under the influence first of his uncle Skeffington Lutwidge, and later of his Oxford friend Reginald Southey. He soon excelled at the art and became a well-known gentleman-photographer, and he seems even to have toyed with the idea of making a living out of it in his very early years.  A study by Roger Taylor and Edward Wakeling exhaustively lists every surviving print, and Taylor calculates that just over half of his surviving work depicts young girls, though about 60% of his original photographic portfolio is now missing. Dodgson also made many studies of men, women, boys, and landscapes; his subjects also include skeletons, dolls, dogs, statues, paintings, and trees. His pictures of children were taken with a parent in attendance and many of the pictures were taken in the Liddell garden because natural sunlight was required for good exposures.  He also found photography to be a useful entree into higher social circles. During the most productive part of his career, he made portraits of notable sitters such as John Everett Millais, Ellen Terry, Dante Gabriel Rossetti, Julia Margaret Cameron, Michael Faraday, Lord Salisbury, and Alfred, Lord Tennyson.  By the time that Dodgson abruptly ceased photography (1880, over 24 years), he had established his own studio on the roof of Tom Quad, created around 3,000 images, and was an amateur master of the medium, though fewer than 1,000 images have survived time and deliberate destruction. He stopped taking photographs because keeping his studio working was too time-consuming. He used the wet collodion process; commercial photographers who started using the dry-plate process in the 1870s took pictures more quickly. Popular taste changed with the advent of Modernism, affecting the types of photographs that he produced.

What did he take photos of?
Taylor calculates that just over half of his surviving work depicts young girls, though about 60% of his original photographic portfolio