In 1927 (at age 34), Henri enrolled as a non-matriculating student at the Bauhaus in Dessau, where she studied photography for the first time with László Moholy-Nagy, developing a close friendship with Lucia Moholy, who strongly encouraged Henri’s experimentation with the camera.

In early 1928, Florence Henri abandoned painting and from then on focused on photography, with which she established herself as a professional freelance photographer with her own studio in Paris – despite being self-taught. Mirrors become the most important feature in Henri’s first photographs. She used them both for most of her self-dramatizations and also for portraits of friends, as well as for commercial shots.

She was an experimental photographer who explored extreme perpective views, multiple exposures, photograms, and photomontages. In addition to portraits of well-known figures of the Paris cultural scene, she also did anonymous portraits ("Portrait Compositions"), many self-portraits, and so-called "Mirror Compositions", which occupy a central place in her body of artistic work.

Henri’s manipulation of mirrors, prisms, and reflective objects to frame, isolate, double, and otherwise interact with her subjects–one of the most distinctive and adventurous features of her photographic work–often confounds viewers’ ability to distinguish between reality and reflection.

Between 1928 and the late 1930s, Henri produced the work for which she is best known, including her mirror compositions, participating in the Film und Foto exhibition in Stuttgart in 1929. She opened a successful studio in Paris and took on advertising projects to supplement her income, continuing to feature mirrors and utilize photographic techniques promoted at the Bauhaus in her professional work.