Since the waterproof case is equipped with a spherical porthole, which is used to reduce the size of the case and fit camera lens, images of straight objects recorded underwater may look distorted or appear less clear compared to those recorded normally outside of water. This is due to the optical refraction underwater being different. This is a normal operation and not a malfunction.
By using the replacement door pack for diving accessory AKA-RD1 (sold separately) in the SPK-AS1 waterproof case, it is possible to prevent image blur and distortion. You can also use the underwater housing MPK-AS3.
By using the "Dive Door" AKA-DDX1 accessory (sold separately) in the waterproof case SPK-X1, it is possible to prevent images from being distorted or blurred.