To realize the application of light field imaging technology in the longwave infrared band, the radiation calibration and nonuniformity in infrared light field imaging were investigated. First, according to the principle of light field imaging and nonuniformity correction, a radiation calibration model for infrared light field imaging was proposed, and the relationship between response drift and nonuniformity was analysed. Next, a standard blackbody experiment was designed to record the image data within 30 hours after the two-point calibration, and the nonuniformity changes of light field data and light field imaging under the same conditions were compared. The experimental results show that within 10 minutes to 30 hours, the nonuniformity of light field data increases from 0.062% to 0.62%, while the nonuniformity of light field imaging increases from 0.024% to 0.27%. Therefore, the effect of response drift on the nonuniformity of infrared light field imaging is affected by the calculation of vignetting and refocusing of the microlens array. Refocusing can effectively suppress the increase in nonuniformity due to response drift.