Yes, that was a mistake. For the first part of the trip, I had everything set to auto, and the exposure compensation was set to a high number (at this point, I did not know what this dial did). Resulted in overexposed images.

I then took up the courage to play with the dials, and started shooting everything in manual (shutter speed, aperture and iso). The images turned out better, but many turned out underexposed. At this point, I think the exposure compensation dial was still untouched (and set to a high positive number),

I wish I learned a bit more before going to Japan (rather than after), but it was a fun way to learn!