Camera panning is one of the most utilized cinematic techniques, and for good reason. It can make otherwise static shots more dynamic, give vistas a more expansive feel, and track the movement of a subject, among other benefits. However, results may appear unusual if the panning rate, settings and method are suboptimal. This article discusses best practices for improving results.
The apparent panning speed is controlled by both the physical rotation of the camera and the focal length of the lens. For the same on-screen effect, a camera needs to be rotated more slowly when using a longer focal length, for example, since these lenses span a narrower angle of view. In the diagram below, the longer focal length lens has to transit twice as many screen widths despite being rotated identically:
Being able to control panning is important because moving too quickly can cause unpleasant visual artifacts. Objects or backgrounds may appear to flash across the screen in discrete jumps, for example, whenever the on-screen displacement is too great compared to the duration between frames. This is commonly referred to as strobing or "judder," and has happened since the early days of film.
Although judder has many contributing factors, it is ultimately determined by how fast a scene moves from one side of the screen to the other. The rule of thumb is to pan no faster than a full image width every seven seconds, otherwise judder will become too detrimental. This rule is especially simple and powerful because it applies regardless of camera lens, model or sensor size.
However, this is not an all-or-nothing limit; images will not immediately become unwatchable faster than seven seconds, nor will they become fully artifact-free when panning slower than this limit. It's just a good starting point. Other factors may also modify the effect . . .
FRAME RATE & SHUTTER ANGLE
The seven second rule of thumb is based on traditional theatrical viewing at 24 fps with a 180 degree shutter angle. Varying either setting can influence the appearance of panning and change the optimal panning speed.
The shutter angle controls the balance between stuttered and blurred panning: larger angles cause panning to appear smoother but more smeared, whereas smaller angles cause panning to appear crisper but choppier. Most cinematic pans are performed near 180°, but special purpose scenes may work better with other settings. When a more fluid, dreamlike effect is desired, one can often get away with faster panning and a larger shutter angle, for example. Similarly, landscape detail may benefit from slower panning and a smaller shutter angle.
The frame rate can also have a big impact on panning. For example, capturing at a higher frame rate (such as 48 or 60 fps) can help smooth the most detrimental high-frequency camera movements if this footage is played back more slowly (such as 24 or 30 fps). Alternatively, high frame rate playback can reduce the appearance of judder or other artifacts without having to decrease the panning speed.
Note: High frame rates are still cutting-edge on the web. For the smoothest playback, use a fast computer, don't move the mouse, and view multiple times to ensure it gets loaded into memory. Otherwise try downloading the videos here.
Using the standard seven second rule of thumb along with other factors, the panning tool estimates the panning speed where judder will likely become too pronounced. The goal is to provide a more accessible tool than the charts and tables commonly referenced in cinematography manuals.
Results should only be taken as a rough guideline for static scenes with constant camera movement. Ultimately, it's a human watching the panning, and what matters is whether the panning looks good to them. Any results should also fit the mood of the scene. High energy scenes can often get away with more abrupt camera movements, for example. However, what feels too fast to one person may feel just right to another, in which case the above calculator can be used as an objective baseline.
Factors in addition to panning speed, shutter angle and frame rate may also be important. These include: