If you are just starting in digital photography, like most people you look at the image review on the monitor after you take a photo. This is a great help to check your composition, but do not depend on it for correct exposure. Remember your eyes adjust for the ambient light, if you are shooting at night or in a dark room you eyes dilate. As a result the image on your screen will appear brighter. And in bright light your pupils constrict so the image may appear darker.
The best thing to do is to learn how to read the histogram that your camera produces for the image. You can see the histogram by toggling through the display screen on your Sony camera. There are many tutorials on line about reading histograms. Learning histograms will also help you in post production when adjusting highlight, shadows and mid tones.
There are 2 more things that might throw someone off Ira. The brightness of the EVF or LCD screen, and the DRO. I fell into that trap myself and thought I got excellent exposure. We lax after a while and take it for granted that what we see is what we get, and forget the true indicator (the histogram).