Difference Between Snapshots and Portraits – Focus and Depth of Field (Part 2 of 5)

This is the second installment of my five part discussion on the differences between snapshots and portraits.

Differences Between Snapshots and Portraits

1. Light and Exposure
2. Focus and Depth of Field
3. Texture
4. Composition
5. Color

Why’s everything so blurry?

If you don’t know why focus is so important, you are likely used to point and shoot compact digital cameras that typically try to put everything into focus. They do that for the simple reason that they don’t know what you want them to focus on.

Focus has two major elements to it:

• The point at which everything is sharpest
• The amount of foreground and background which is acceptably sharp.

The actual depth of field is based on the sensor size (i.e. Circle of Confusion), lens focal length and distance to subject combination. The actual calculated is far too complicated to be explored in the post. However, trust me when I state … by adjusting the aperture of the capture, a photographer can control how much foreground and background is actually in focus. A larger aperture (small f-stop number) will result in a smaller depth of field. Likewise, a smaller aperture (large f-stop number) will result in a larger depth of field.

Why would you want any of the photo to be blurred?

That’s an excellent question! First and foremost, the technique is used to help guide the viewer’s eyes to what the photographer wants them to focus on (no pun intended!). The most common “focus point” is the subject’s eyes allowing the viewer to connect the most with the subject. Even so, other techniques include focusing on the hand from an outstretched arm thereby throwing the main subject out of focus.

The possibilities are truly endless. Grab your camera and take it out of the Program or Auto mode and put it in the A mode (Aperture Priority) to give it a try. This mode will let the camera calculate the necessary exposure and adjust the shutter speed accordingly for you automatically. Try taking photos of the same subject with small apertures and large apertures. What did you notice? What do you like better?

Is it possible for the aperture to be too large (i.e. the f-stop being too small)? What do you think?