When creating an image manually there are a lot of factors that need to be taken into consideration in order to produce what you initially envisioned. Things like composition, lighting, shutter speed, aperture, ISO, white balance, etc. make for a rather long laundry list of items and at times certain elements can get overlooked.
For me, one element that can definitely change the feel of an image is the depth of field. This is particularly true when I am shooting close-up or macro. There have been many times when I have carefully found a composition that I really like, set up my tripod, double checked my exposure, fired away, and left the situation feeling good about what I shot, only to be somewhat disappointed when I opened the images on my computer. And the source of the disappointment? Depth of field- either too much or not enough. Let’s look at some examples of how depth of field (aperture) can impact images. These examples are straight out of the camera with no editing whatsoever.
Aperture 5.0 Aperture 14
Aperture 5.6 Aperture 22
Aperture 6.3 Aperture 13
Notice all the differences between the images, some subtle, some more dramatic. There is no right or wrong but merely creative differences. So what is this telling us? You should take into consideration what elements you want in your final image. Do you want tack sharp front to back? Do you want some softness? Do you want blurred backgrounds? All of these answers are found with depth of field.
Sometimes, however, I may not be exactly sure what will work in the final image. Maybe I want some softness, but how much? Are things really sharp all the way through? Do not rely on the LCD screen on the back of your camera to answer these questions! The screen can give you a hint but it does not tell you everything. The point is after you have a composition that you are pleased with, remember to take several shots, varying the aperture with each one. In this way you will have an opportunity to pick the one that perfectly suits your creative vision. Happy shooting.