When you hand hold your camera and depending on the shutter speed setting, you can cause unwanted “image blur” just from hand and body movement resulting in a “soft image“.
Looking at the image of the girl on the left, f/5.6, 1/60, ISO 200, @ 200mm, notice the image is sharp, versus the image on the right which is what we refer to as a “soft” image. If you were to magnify the image on the right to a 1:1 magnification you would see the blurry edges around the girls eyes, nose, mouth, and hair. Click on the images to view a larger size.
Check out this YouTube resource to help with how to properly hand hold a DSLR or bridge camera. SLR Lounge – 6 Ways to Hold a Camera for Slow Shutter Speeds and Sharp Images (10 min. 58 sec.)
The general rule of thumb when hand holding your camera is to choose a shutter speed equal to or greater than the focal length. For the above example image of the girl we used a shutter speed of 1/60 with a focal length of 200mm. Following the general rule the shutter speed should have been at a minimum of 1/200. By not using a fast enough shutter speed it resulted in a number of undesired soft images during the photo shoot. Lens image/optical stabilization or sometimes referred to as vibration reduction can help when using slower shutter speeds which will be discussed in a future article.
Choosing the shutter speed to minimize motion or freeze the subject will be covered in the next lesson.