For best outputs: Sampler: DPM++ SDE Steps: 5 ~ 8, cfg 2, CLIP skip 2 VAE: none. Pos prompt: the model is realistic and doesn't need much. Adding "Photorealistic, stunning details, 8k, raw photo, 8k uhd, film grain, unreal engine 5, ray tracing, dynamic, Nikon d850, Depth of field 270mm, Amaro, Golden ratio" and similar increases the quality slightly. Neg: nothing or simple things like "CGI, Unreal, Airbrushed, Digital, dark, oversaturated".