Final answer:
Julia Margaret Cameron is recognized for pioneering the use of close-ups in portrait photography, helping to establish photography as a fine art during the Victorian era.
Step-by-step explanation:
The artist known for pioneering close-ups in portrait photography is Julia Margaret Cameron. Cameron was a Victorian era practitioner who played a significant role in making photography a fine art. Her innovative techniques, especially the use of close-up portraits, greatly contributed to the development of photographic art, setting her apart from contemporaries and making her work distinct in the history of photography.