My friend bought an EOS 3 and loves it. She offered to loan it to me. I read the manual thoroughly before using it. I took photos of my young grandson playing in the bathtub, window right next to the tub, shade pulled up, beautiful late afternoon sun reflecting off his skin. I shot in manual mode with my friend's 135 mm lens, 3-4 feet away. Film was Fugi pro 160S processed at a professional lab that I always use. I can't remember my shutter speed or aperture - probably 125 and low f stop numbers. In fact my husband commented that I should drop the shade because he felt there would be too much light. The outdoor shots were taken with my friend's zoom lens and they were underexposed too. I could only salvedge 2-3 shots. I know for sure it's not the camera or lenses causing the problem. I've seen photos from this camera when I returned it. I'm use to my Elan 7 and I rarely, if ever, get underexposed shots. My friend shoots in auto so she can't help me. I plan to buy this camera in the near future. Can anyone give me some idea what I might have done.