I am new to photography and use a Nikon D3200 to shoot jewelry in a light tent. I use the original 18-55mm f/3.5-5.6 lens with Xit XTETN Auto Focus Macro Extension Tube for macro shots.
I have this problem where I would be shooting perfect images under a certain setting, then all of a sudden the light drops even though nothing changed (none of the light, settings, objects changed). See below two pictures taken a few seconds apart; and I took a third picture with a slower shutter speed but the picture came out even darker. This happened to me a few times already and I can't figure out why. Any advice?