  Among the common applications of plenoptic cameras are depth reconstruction
and post-shot refocusing. These require a calibration relating the camera-side
light field to that of the scene. Numerous methods with this goal have been
developed based on thin lens models for the plenoptic camera's main lens and
microlenses. Our work addresses the often-overlooked role of the main lens exit
pupil in these models and specifically in the decoding process of standard
plenoptic camera (SPC) images. We formally deduce the connection between the
refocusing distance and the resampling parameter for the decoded light field
and provide an analysis of the errors that arise when the exit pupil is not
considered. In addition, previous work is revisited with respect to the exit
pupil's role and all theoretical results are validated through a
ray-tracing-based simulation. With the public release of the evaluated SPC
designs alongside our simulation and experimental data we aim to contribute to
a more accurate and nuanced understanding of plenoptic camera optics.
