In darkness, Ca²⁺ enters through cGMP-gated channels in the rod outer segment and exits via Na⁺/Ca²⁺-K⁺ exchange. Light closes the channels and decreases Ca(2+i), but the relationship between light, current, and Ca(2+i) has remained unclear. We have previously shown that intense light evokes a release of Ca²⁺ within the outer segment (Matthews & Fain, 2001, 2002), most clearly seen when a rod is superfused with a 0Ca²⁺/0Na⁺ solution designed to oppose surface membrane Ca²⁺ fluxes (Matthews et al. 1988; Nakatani & Yau, 1988). It seemed possible that this release would contribute to changes in Ca(2+i). Using fluo-5F, rapid solution exchange, and suction pipette recording from rods isolated from salamanders killed humanely by stunning, decapitation and pithing, we now show that after saturating light the circulating current, Ca(2+i) and the light-releasable pool of Ca²⁺ all recover with a nearly identical exponential time course. Steady background light produces a maintained decrease in current, which is accompanied by a near-proportional decrease both in Ca(2+i) and in the light-releasable Ca²⁺ pool. These experiments show that the major determinant of Ca(2+i) in the outer segment following just-saturating illumination is the rate of influx through the channels, and that the light-releasable pool makes only a minor contribution. The amount of Ca in the light-releasable pool appears to be determined principally by Ca(2+i) except during bright light exposure. This is most clearly seen if the rod is illuminated in 0Ca²⁺/0Na⁺ solution, since even relatively small bleaches in this solution deplete the pool even in the absence of a light-induced decline in Ca(2+i), indicating some special effect of pigment bleaching on Ca²⁺ buffering and/or sequestration. This effect is spatially localised, since exposure to a narrow slit of intense light in 0Ca²⁺/0Na⁺ solution eliminates the releasable pool in that location (after laser bleach fluo-5F fluorescence 0.99 ± 0.01 of initial dark level, mean ± S.E.M., 7 cells) but not in neighbouring unilluminated regions of the outer segment (after laser bleach fluo-5F fluorescence 1.23 ± 0.03 of initial dark level, 7 cells, significant at 0.1 % level, Student’s unpaired t test, t = 8.7).