A dictionary of photography for the amateur and professional photographer (1889)
Wall, E. J. (Edward John), 1860-1928 · New York : E. & H.T. Anthony · leaf 113
DICTIONARY OF PHOTOGRAPHY. I03 and an English optician, in 1858, introduced a lens having a con- cave glass in place of the diaphragm to lengthen the focus and flatten the field, and Dallmeyer introduced his famous triplet (fig. 9), which at the present time is much used and admired. … Fig. 9. Single lenses were first of all of the kind shown in fig. 4, with which extremely small diaphragms are necessary to reduce Fig. zo spherical aberration and distortion. This was improved on by Grubb, and his lens is shown in fig. io, in which a crown-glass lens of meniscus form is presented…
Photography
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