This is a comparison between setting the white balance to auto and presetting it with a sheet of white copy paper.
Literal
White-balance [obj-を] auto [to-に] did-case [and-と] white copy-paper [with-で] preset-did-case [gen-の] comparison [copula-です].
Classic formal compact structure: ~した場合と~した場合の比較 'a comparison between the case of doing X and the case of doing Y.' 場合 'case / situation' is the key noun Japanese uses to build hypothetical or conditional contrasts in written and technical prose. The instrumental で marks 'with / using' the copy paper; the に on オート marks it as the end-state of する. にする 'to set something to X' is the core transitive 'make-it-X' pattern.