Six Correct Exposures versus one creatively correct one
"What difference does it make which combination of aperture and shutter speed I use? If my light meter indicates a correct exposure, I'm taking the picture.
Perhaps you think like this; Whether you shoot in program mode, shutter-priority mode, aperture-priority mode, or even manual mode, you may think that the light meter indicates that everything's okay, it must be okay to shoot; right well let’s see!
The trouble is that this kind of logic makes about as much sense as a chef who sets the same oven temperature for every one of his master creations, it’s going to be correct for some of his recipes but at what cost? If you want to shoot only "correct exposures of anything and everything, eventually, you might even record a correct exposure.
However as a professional photographer, I want to capture the image correctly every time I hit the shutter; especially when providing my photography service at a wedding.
Most picture-taking situations have at least six possible combinations of stops and shutters speeds that all result in a correct exposure. Yet, normally; just one of these combinations of F-stops and shutter speeds is the creatively correct exposure.
As we've already learned, every correct exposure is nothing more than the quantitative value of an aperture and shutter speed working together within the confines of a predetermined ISO. But a creatively correct exposure always relies on the one f-stop or the one shutter speed that will produce the desired exposure.
Let's pretend for a moment that you're at the beach taking pictures of the Bride & Groom in harsh sunlight, I’m using the image of my daughter here; this image was taken at our swimming pool on our summer holidays in the Southwest on a superb sunny day, where Ilanna just popped out of the pool, the sun was very harsh and the sun reflecting off the water was very bright; I knew I would have to reduce the ambient light to keep her wonderful skin tones and the blue of the swimming pool.
Because of the available light, it was a no brainer, I set ISO 100 on the camera, I wanted to keep the blues of the pool in the photograph so I selected an aperture of an F5.6 the next setting to adjust was my shutter speed as there was so much light I used my N/D filter to allow me to keep the flash sync speed to the cameras optimum which is at 1/180 (Check out your cameras optimum flash sync speed) adjusting the shutter speed, gave me a perfect exposure (indicated in the viewfinder)
There are several combinations of apertures (F-stops) and shutter speeds I could have used and still record a correct exposure but due to the harsh lighting and the effect I particular wanted for this photograph this is what I chose, remember I chose this not the camera!
This creative approach toward exposure will reap countless rewards if you get in the habit of looking at a scene and determining what combination of aperture and shutter speed will provide you with the most dynamic and creative exposure for that subject. The choice of exposure is many; so why not make it the most creative exposure possible?