EXCERPT page containing first few paragraphs. 2019-06-17 06:42:49
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This dual series with with lens tilt shows two aperture series with the same tilt but at different focus positions: one without compensation for focus shift, and one with compensation for focus shift. The pairing makes for a graphic demonstration of just 'insane' focus shift can be: I don’t consider an optimal compromise of this degree acceptable under any circumstances for a tilt/shift lens.
Tilt is in theory an outstanding feature in that it can evade the limitations on depth of field, but when one also has to deal with focus shift, its usefulness drops considerably: it is hard enough to fine-tune the amount of tilt, to which image sharpness is highly sensitive, while having to deal with the optical design idiocy of a strong focus shift to complicate matters. A “good” lens is one that is sharp and predictable, not one that has to be second-guessed, or compensated for—the risk of error goes way, way up when having to compensate for focus shift.
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