Rule/DOF

Rule of Thirds

Composition and what it means

Depth of Field

History Lesson

The zone of acceptable sharpness within a photo that will appear in focus. In every picture there is a certain area of your image in front of, and behind the subject that will appear in focus.

Composition is the key element of the photography. Apart from practicing technical controls of the camera to achieve various effects, one has to learn to compose a scene before taking shots. Composing a scene means arranging different visual elements in the field of view for the shooting purpose, so that we have the desired placement of various elements in the final photograph.

How does distance change DOF?

The closer your subject is to the camera, the shallower your depth of field becomes. Therefore, moving further away from your subject will deepen your depth of field.

Rule of Thirds vs Golden Ratio

How does Aperture control DOF?

The first person to cite and name the Rule of Thirds was an 18th-Century painter, engraver, and writer named John Thomas Smith.

Smith lived in London, from 1766 to 1833, and was known to many as “Antiquity Smith,” after his work Antiquities of London and its Environs. He eventually took the position of Keeper of Prints at the British Museum.

In 1797, Smith wrote a short book entitled Remarks on Rural Scenery. It covers “various features and specific beauties in cottage scenery” and, in the chapter “Of Light and Shade,” it discusses a work by Rembrandt called The Cradle, in which “two thirds of the picture are in shadow.” He writes, “Two distinct, equal lights, should never appear in the same picture: One should be principal and the rest sub-ordinate, both in dimension and degree: Unequal parts and gradations lead the attention easily from part to part, while parts of equal appearance hold it awkwardly suspended as if unable to determine which of those parts is to be considered as the subordinate.”

Golden ratio is a mathematical constant equals to 1.618 discovered by an Italian mathematician Leonardo Fibonacci around 1200 AD. It is the ratio of two division of one sole unit in such a proportion that the ratio of larger part to the smaller is accurately equal to the ratio of the sum of larger and smaller part of the unit concerned to the larger part. He found that the golden ratio has existed in nature since the beginning; that is why it is also known as the “divine proportion”. It’s all around us.

Large aperture = Small f-number = Shallow (small) depth of field

Small aperture = Larger f-number = Deeper (larger) depth of field

Why it works

Think of it like this: If your subject is in the middle of the image, it's considered static. Your eye is drawn to it then has nowhere to go from there because the object is equal distance from all sides. Therefore when your subject is positioned closer to one of the edges, it forces your eye to follow it…to find it. This allows the viewer to linger on your image longer. It makes for a more captivating photo because it's almost interactive. Like a conversation going on between the photo and you.

How is DOF distributed within an image?

It is usually about one third in front and two thirds behind your focal point, but as your focal length increases it becomes more equal.

When should I use a shallow vs deep DOF?

Using a shallow depth of field is a good way to make your subject stand out from its background and is great for portrait photography. Shallow DOF can also be useful in wildlife photography, where you want the subject to stand out from its surroundings. Shallow depth of field is also effective for sports photography where many times you want to separate the athlete from the background to bring attention to them.

In landscape photography it is important to get as much of your scene in focus as possible. By using a wide angle lens and a small aperture you will be able maximize your depth of field to get your scene in focus.