Definition
Depth of field is the distance between the nearest object and the furthest object.
Depth of Field (DOF) is the front-to-back zone of a photograph in which the image is razor sharp. As soon as an object (person, thing) falls out of this range, it begins to lose focus at an accelerating degree the farther out of the zone it falls; e.g. closer to the lens or deeper into the background. With any DOF zone, there is a Point of Optimum focus in which the object is most sharp. There are two ways to describe the qualities of depth of field - shallow DOF or deep DOF. Shallow is when the included focus range is very narrow, a few inches to several feet. Deep is when the included range is a couple of yards to infinity. In both cases DOF is measured in front of the focus point and behind the focus point. DOF is determined by three factors – aperture size, distance from the lens, and the focal length of the lens.
Aperture
The aperture is the opening at the rear of the lens that determines how much light travels through the lens and falls on the image sensor. The size of the aperture’s opening is measured in f-stops - one of two sets of numbers on the lens barrel (the other being the focusing distance). The f-stops work as inverse values, such that a small f/number (say f/2.8) corresponds to a larger or wider aperture size, which results in a shallow depth of field; conversely a large f/number (say f/16) results in a smaller or narrower aperture size and therefore a deeper depth of field.
Manipulating the aperture is the easiest and most often utilized means to adjust Depth of Field. To achieve a deep, rich and expansive DOF, you’ll want to set the f-stop to around f/11 or higher. You may have seen this principle demonstrated when you look at photos taken outside during the brightest time of the day. In such a case, the camera is typically set at f/16 or higher (that Sunny 16 Rule) and the Depth of Field is quite deep - perhaps several yards in front of and nearly to infinity beyond the exact focus point. Let’s take a look at these two photos as examples. The photo on the left has an expansive DOF, most likely shot around noon (notice the short, but strong shadows), with an f/22 aperture. The photo on the right has an extremely shallow DOF; probably an f/2.8 aperture setting. However, to achieve an identical proper exposure, the shutter speed is probably closer to 1/1000th to compensate for the increased amount of light entering the lens at f/2.8.
Comments
This photo is good because it has a strong deep depth of field and the steps give this depth in a very apt way leading up to the well illuminated castle, though Cinderella is the main focus of the photo after you have considered her, your eye drifts back towards the castle making the depth very good , this photo tells a story very well and i really like the way it is assembled, the lighting and also the depth.
If I compare this to this other picture of hers, the feel is very different. The other picture has a magical feel but even though they are both based on two successful fairy tales, there is no magical aspect to the Alice in Wonderland. The depth is shallower than in Cinderella as it's all about the clothes for this Vogue shoot. The models are the subjects in both pictures but there is a big disparity in them which clear.