I am trying to learn a lot about photography as fast as I can. I am watching a lot of video, reading this forum and magazines. Whenever I see a photo that somebody submits for critique, there seems to be a lot of different opinions about the photo. Some say there are too many shadows on the subjects face, others like how the photographer left the shadows to show depth....I'm confused on what's the best way or is it all in the eye of the beholder? I may take a photo and purposely leave it dark for the effect. Is this wrong?
Look at the choices...
One choice is flat frontal light, flash on the camera for example. This illuminates everything the lens sees very evenly. Even to a fault. Shadows are hidden BEHIND the subject. Which might be good for a few subjects (which are typically flat themselves), but the flat lighting does not show shape of the subject. We need shadows to show shape.
So, moving the flash off camera is the first step. This makes very discernable shadows which the camera angle can see now, and which better shows the shape of the subjects curves.
But, such shadows can be very dark then, objectionable in their own right.
So then we add a weaker fill flash near the camera that will evenly fill those shadows (that the lens sees), to make them much less dark. Then the shadows become just weaker tonal gradients, mild shading, perfect for showing shape without being too dark or contrasty.
Look at the first picture Mike D90 posted here. It is NOT flat lighting. Shadows are NOT dark. Yet the mild shadows (gradient tones) are very definitely present to show contour, curves and shapes. The contrast vs flat frontal light is very dramatic. Beginners can look at the shirt to get the idea fast. The shadows show the shape of the contours in the shirt. Some degree of this is essential. Too much becomes too much.
A snapshot of a human in the bright sun is a dramatic example. Dark shadows, terrible result. But simply pop up the internal flash to add fill in TTL BL mode makes tremendous difference (if subject distance is not too far for tiny flash). It can make trash be a good picture.