The problem of observation of an opaque object through a surface-bounded layer of a scattering medium is solved based on the small-angle approximation with the allowance made for the formation of a shadow zone. It turns out that the image contrast can have a local extremum of best visibility inside a medium. It is shown that the object visibility can increase monotonically with the increasing depth in a turbid medium. The conditions under which this improvement occurs and the contrast extremum is reached are numerically evaluated.