A lot of modern (DSLR or mirrorless era) lens intentionally accept a lot of optical flaws that are easy to correct with software (e.g. vignetting; sometimes eve

A lot of modern (DSLR or mirrorless era) lens intentionally accept a lot of optical flaws that are easy to correct with software (e.g. vignetting; sometimes even mechanical/hard vignetting where the lens does not fully cover the sensor); to prioritise addressing flaws that are difficult to correct with software (i.e. resolution, sharpness). The software in the camera automatically correct these things before you see it; and when it's particularly bad, usually this correction cannot be disabled. On most brands, RAW will tell you something closer to what the sensor is really seeing.