While diagnostics exist for quantifying droplet fields in an atomized spray, direct imaging is needed to quantify and characterize the interfacial instabilities responsible for droplet generation. To study these interfacial instabilities in high-pressure sprays used in direct-injection engines, resolving power on the scale of 1 mu m is required. Imaging systems must also work around high-pressure optical chambers that limit the minimum working distance to approximately 50-100 mm. To study these sprays via direct imaging, commercial long-range microscopic lenses and collimated backlit illumination are typically used. These lenses limit resolving power to around 5 mu m with visible light, and backlit illumination only visualizes the spray periphery as light is scattered and extinguished in the spray core. In this work we introduce an ultra-high-resolution imaging and illumination system that circumvents these limitations. This system enables resolved imaging of the near-nozzle region of diesel sprays under engine-relevant high-backpressure conditions. An opal diffuser is placed adjacent to the injector tip to increase light dispersion. This improves spray core illumination by increasing the solid angle of illumination. This is coupled with a 1 mu m resolving two-piece lens, a 24 MP camera, and a high-power 4 ns backlight. Using this system we image primary atomization in diesel sprays. These images show fluid structures on the emerging jet not visible using collimated backlighting and long-range microscopes. This system visualizes an intact liquid core and surface instabilities in the near-nozzle region. The implications of these features for atomization models are then discussed.