Cameron's photographic career was short, spanning eleven years of her life (1864–1875). In 1863, when Cameron was 48 years old her daughter gave her a camera as a present, thereby starting her career as a photographer. Within a year, Cameron became a member of the Photographic Societies of London and Scotland. In her photography, Cameron strove to capture beauty. She wrote, "I longed to arrest all the beauty that came before me and at length the longing has been satisfied."
The basic techniques of soft-focus "fancy portraits", which she later developed, were taught to her by David Wilkie Wynfield. She later wrote that "to my feeling about his beautiful photography I owed all my attempts and indeed consequently all my success". Cameron was sometimes obsessive about her new occupation, with subjects sitting for countless exposures in the blinding light as she laboriously coated, exposed, and processed each wet plate. The results were, in fact, unconventional in their intimacy and their particular visual habit of created blur through both long exposures, where the subject moved and by leaving the lens intentionally out of focus. This led some of her contemporaries to complain and even ridicule the work, but her friends and family were supportive, and she was one of the most prolific and advanced of amateurs in her time.
Her enthusiasm for her craft meant that her children and others sometimes tired of her endless photographing, but it also means that we are left with some of the best of records of her children and of the many notable figures of the time who visited her.
During her career, Cameron registered each of her photographs with the copyright office and kept detailed records. Her shrewd business sense is one reason that so many of her works survive today. Another reason that many of Cameron'sportraits are significant is because they are often the only existing photograph of historical figures. Many paintings and drawings exist, but, at the time, photography was still a new and challenging medium for someone outside a typical portrait studio.
The bulk of Cameron's photographs fit into two categories – closely framed portraits and illustrative allegories based on religious and literary works. In the allegorical works in particular, her artistic influence was clearly Pre-Raphaelite, with far-away looks and limp poses and soft lighting.