Sharpness

We want our pictures to be sharp and clear. Or, at least we want to be in control of which parts of our photo are sharp and clear. Sharpness has several meanings in this context, and several factors to consider.

• Focus
• Camera movement
• Subject movement

A lens, in this case a complex camera lens, gathers in light and can focus that light. Imagine a tiny point of light at ten feet away. If the camera lens is not set at ten feet then that point of light will be a blurry circle. As we focus closer and closer to ten feet that circle gets smaller and smaller. As we focus at exactly ten feet that point is finally focused by the lens as a single point. That’s a very overly simple explanation of focus.

Conversely, if we focus on something at ten feet away, objects nine or 11 feet away will be slightly out of focus, while objects five or 15 feet away will be even more blurry. (One kind of blurriness is from being out of focus).

Let’s continue this thought experiment. If I focus the camera at something exactly ten feet away, then everything ten feet away will be in focus. You could draw a circle around you at ten feet, with your camera at the center. Everything on the circle will be in focus. And everything less than or further than ten feet will be out of focus to some degree.

That degree of ‘out of focusness’ (a phrase I just made up) is called Depth of Field. Remember that phrase. We’ll come back to it in future lessons.

You can control what is in sharp focus on your phone as shown in the phone tutorials. One factor that controls depth of field is the size of the sensor of the camera. Phones have very small sensors so they can fit in your phone and your phone can fit in your pocket.  One side effect of this is that most of your image will be in focus, most of the time. In fact, it is difficult to make the background blurry without manipulating the image with software fixes. That soft blurry background that can be so pleasing is difficult to create with your phone.

Camera and subject movement are affected by shutter speed, and both can cause a loss of sharpness. If the camera moves while we take a photo, the entire photo will be blurry (a different blurry from out of focus blurry).

This can definitely be a problem with your phone. In darker situations your camera will slow the shutter sped to let in more light, as any camera would. This can create blurry photos for two reasons:

• If you don’t hold the camera steady, the whole image will be blurry.
• If your subject is moving as you take the photo, they will be blurry as well.

If our subject moves while we take the photo, he, she, or it may be blurry depending on how fast he, she, or it is moving and the shutter speed.