The 8K ultra-high-definition television (UHDTV) is a next generation television system with a high realistic sensation. High dynamic range (HDR) is a new standard for television systems, defined in Recommendation ITU-R BT. 2100. Hybrid log-gamma (HLG) is one of the HDR standards, jointly suggested by NHK (Japan Broadcasting Corporation) and BBC (British Broadcasting Corporation), and is highly compatible with the conventional standard dynamic range system. Although a "full-featured" 8K camera with HLG has already been developed, most existing 8K cameras do not comply with the HLG standard. In this paper, we describe a method for adapting existing 8K cameras to HLG, thus enhancing their dynamic range. Based on subjective image quality evaluation results, we propose a guideline to choose the dynamic range setting for each shooting scene, considering the noise performance of the particular used 8K camera.