  A recent paper demonstrated that two lenslet arrays with focal lengths f_1
and f_2, separated by f_1 + f_2, change the direction of transmitted light rays
approximately like the interface between isotropic media with refractive
indices n_1 and n_2, where n_1 / n_2 = - f_1 / f_2 [J. Courtial, New J. Phys.
10, 083033 (2008)]. This is true if light passes through corresponding
lenslets, that is lenslets that share an optical axis. Light can also pass
through different combinations of non-corresponding lenslets. Such light can be
either absorbed or allowed to form "ghost images"; either way, it leads to a
limitation of the field of view of confocal lenslet arrays. This paper
describes, qualitatively and quantitatively, a number of such field-of-view
limitations.
