There are two things a 21st-century reader of Camera Lucida must keep in mind right from the start. First, Roland Barthes' book on photography was written in 1979, about a decade before Photoshop and at least two decades before the proliferation and ubiquity of inexpensive digital cameras and social media sites. Second, Barthes is clear about dismissing the artistic intentions of photographers (Barthes calls them "Operators") and about systematically rejecting objective values for the art form.
With those cautions in mind, a reader can weigh the special value of Camera Lucida. Barthes provides original insights on the medium, and his insights are useful to a broader consideration of the role of subjectivity in meaning. Barthes, of course, is a very skilled writer, and while the book is dense, Barthes' prose provides much pleasure, especially in the context of a personal reflection. Geoff Dyer and Geoffrey Batchen have noted the Proustian-like refinement of Barthes' sophisticated musings.
Camera Lucida is divided into two equal parts of 24 short sections each. The first part is an often digressive meditation on the nature of photography, and the second is mostly an intense analysis of one photograph, the Winter Garden photograph of his mother. In both parts, Barthes' habit of building from an intellectual or critical framework—foregrounding his own terminology and using exhaustive elaborations—is equal to his ultimate assertion of the subjective having priority. His concepts of punctum and studium seem to have become part of the essential lexicon in criticism of the medium.
Having read Camera Lucida and On Photography (Susan Sontag) several times each, I prefer the latter, especially for teaching students to think critically about looking at photographs. Barthes' book is highly idiosyncratic, while Sontag's addresses key issues more directly. I suppose the two complement each other, but Sontag is more open and less reductive about the medium's eidos. Barthes' book is ultimately a memorable exercise of the ego: "So I decided to take myself as mediator (mathesis singularis) for all Photography," and "So I make myself the measure of all photographic 'knowledge.'"
Sometimes I find myself wondering if Camera Lucida just happened to be about photography. Barthes was prompted to write shortly after the death of his beloved mother, and he had written about photography before, but an intellectual of his stature could make similar, sentimental assertions about a variety of artistic enterprises (i.e. culinary arts, fashion, popular music.) What's problematic is that Barthes equates the photomechanical operation of photography with its eidos; this is a fundamental flaw of his proposals.
In his introduction to the English translation, Geoff Dyer makes a really important point about Barthes' rhetoric. Dyer says Camera Lucida is a beginning, a setting forth. It's true: Barthes is continually setting forth, beginning again and again, and returning to aphorisms previously stated. Despite my reservations about the book, I grudgingly respect the author's mode. After all, in his priority for the subjective—a subjective that is inseparable from his status as Roland Barthes—he has cleverly created a perspective that thwarts or deflects objections, hasn't he.