On the Sampling tab, you can adjust controls that affect motion blur. Adjust:
• motion blur samples - to set the number of samples to render per pixel when motion blurring.
• shutter - Enter the number of frames the shutter stays open when motion blurring. For example, a value of 0.5 would correspond to half a frame. Increasing the value produces more blur, and decreasing the value less.
• shutter offset - Select when the shutter opens and closes in relation to the current frame value when motion blurring:
• centered - to center the shutter around the current frame. For example, if you set the shutter value to 1 and your current frame is 30, the shutter stays open from frame 29.5 to 30.5.
• start - to open the shutter at the current frame. For example, if you set the shutter value to 1 and your current frame is 30, the shutter stays open from frame 30 to 31.
• end - to close the shutter at the current frame. For example, if you set the shutter value to 1 and your current frame is 30, the shutter stays open from frame 29 to 30.
• custom - to open the shutter at the time you specify. In the field next to the dropdown menu, enter a value (in frames) you want to add to the current frame. To open the shutter before the current frame, enter a negative value. For example, a value of -0.5 would open the shutter half a frame before the current frame.
• randomize time - adjust this to add randomness to the distribution of samples in time so they don’t produce regularly spaced images. The larger the value, the larger the time difference between the samples.
• shutter opening - to set the shutter opening behavior. Select:
• none - to use the default shutter opening method, resulting in instantaneous timing to open and close.
• linear - to set the shutter to open and close in linear intervals.
• bezier - to set the shutter to open and close more gradually, according to a Bezier curve.