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Optical Alignment

Keep it parallel.

In the course of testing these lenses, it became clear that optical alignment when shifting might be an issue: whether focal plane and sensor are actually parallel and whether they remain so when the lens is shifted.

Misalignment could also potentially ensue when the lens is rotated.  This problem is potentially worse with the PC-Nikkors, because rotation is required if stitching center/left/right frames for a composite image, as compared with the Schneider, which has bi-directional shifts.

The test frame further below was taken in portrait orientation with 11mm vertical shift.  It was used to determine whether sharpness was consistent across the frame when these lenses were shifted.  This was not the original goal for this shot, but the discovery of inconsistent sharpness across the frame made it the goal.

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Since 2006, Diglloyd Advanced Photography is the authoritative review and reference for DSLRs and their lenses: Canon and Nikon primarily, but also Pentax and some medium format. Reviews of key DSLRs are included, but the primary focus is on lens performance. Also included is a wealth of technique and workflow approaches.

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