Shutter Speed and Motion Blur
One of the advantages of shooting in Shutter-Priority or Manual mode on your DSLR is the ability to add creative effects to your photos. One creative effect, that in some cases can really enhance an image, although in other cases can also ruin one is motion blur. If you’re capturing a grooms wedding speech and later find a blurred hand, that photo is going to be significantly less monumental than if it had been captured crisp and sharp. Similarly, many times high-speed action shots are preferred to be crisp and sharp. Alternatively, if you are photographing a moving bicyclist or a vehicle and can convey a feeling of motion in that picture, then motion blur can greatly enhance and add a realistic feel to the image.
While an incorrect exposure can often be corrected in post-processing, motion blur cannot. The image must be captured correctly in the moment. Motion blur is introduced by adjusting the camera’s shutter speed to change the amount of time the shutter is open relative to any motion of the subject. If the shutter is kept open long enough for the subject to move in the frame, motion blur will occur.
Using a longer shutter time can also be used to create various artistic effects in an image.
Alternatively, if the shutter is opened and closed fast enough, even an incredibly fast moving object can appear frozen in time.
While amazing effects can be generated by using a long shutter speed, it can also have adverse effects if used incorrectly.
Another problem that can arise from using too long of a shutter speed is camera shake. For a sharp image, not only must your subject be still relative to the shutter speed, but the camera must remain completely still while the shutter is open. A typical rule of thumb for non-image stabilized cameras/lenses is the shutter speed should be at least equal to one divided by the focal length.
Minimum shutter speed (sec) = 1/Focal Length (mm)
However, with proper camera holding techniques, setting your camera to burst mode, and a little practice you can often get a crisp shot while violating this rule. Additionally, using an image stabilized camera or lens will also allow you to typically go 1-2 stops lower.
Shutter speed determines motion blur. Choosing the correct value allows a photographer to deliberately introduce motion into a photo, or to capture a crisp sharp image. Shutter speed also affects exposure, and so the value chosen effects the required aperture and ISO, which further affect the final image. This seemingly complex interaction is greatly simplified with a solid understanding of the exposure triangle and some practice. In the mean time we have provided a table to provide as a general guideline for setting shutter speed.
1/4000 Crisp images with very fast moving objects – Water splashing
1/2000 Crisp images with fast moving objects – Vehicles, animals
1/500 Crisp images with medium rate moving objects (runners, cyclists)
1/125 Crisp portrait or group photo / Motion blurring for vehicle wheels
1/30 -1/60 Motion blurred images of cyclists, runners
> 1/2 Blurring moving water