He is best known for his pioneering photographic work with David Octavius Hill .
He is best producing some 2500 calotypes , mostly portraits , within 5 years after being hired by Hill in 1843 , before his life was cut short .
He is best known for his pioneering photographic work with David Octavius Hill and producing some 2500 calotypes , mostly portraits , within 5 years after being hired by Hill in 1843 , before his life was cut short .