Though Johnston never won the critical acclaim of Alfred Stieglitz or other artistic photographers of her day, she did concentrate on photography as an art form.

In 1898, the year she exhibited at the New York Camera Club, she sent some prints to Stieglitz, and he wrote to her that “your work is capital, & I shall be glad to see more of it when you get to New York.” That she thought in artistic terms often comes through in her observations. “It is wrong to regard photography as purely mechanical.” (It was mechanical up to a point, she conceded.)

Her contribution to photography was not in technology or in artistic innovation but in excellence as a practitioner of her art. Perhaps her genius was in doing the ordinary exceptionally well.

Though Johnston did mostly documentary and portrait photography in the 1890s, she earned a reputation as an artistic photographer, one of the vanguard.