Learn about vignetting in filmmaking, what causes it, and how to use it in your favor.
Often times in digital video the sole difference between a video effect and a video equipment malfunction is intent and motive. If the result is the same it is hard to decide what one actually occurred. The real test here is if the final image can be justified within the vision of the director.
This is exceptionally true with certain lens aberrations. These lens aberrations are types of distortions or interferences that happen during the formation of the two-dimensional camera picture by the lens. There are a number of different ones that happen, including the "field curvature" aberration that happens when the lens is in a perpendicular position and the center/edges lack smoothness. Vignetting is another phenomenon that can be considered an aberration by some, but really stands alone as its own kind of interference.
What Vignetting is in Film and Video?
What vignetting refers to is when there is a reduction in light from the center to the outside frame. Essentially an image that displays vignetting will be clear and bright in the center and dark around the edges. This is a natural occurrence when you take a small formatted lens and use it in a larger format, which is why people warn about using 16 mm lenses in a 35 mm camera. If you are in a situation where you are using a small formatted lens in a large formatted camera try to avoid using wide angeles or infinite zoom. Both of these elements tend to highlight your image's vignetting.
Vignetting Video Effect
Vignetting is also a stylistic choice that many directors make. This can be done to reference the visual style of older cinema types, especially those used in the silent era. Make sure that you have a clear reason to do this and that you can complete the motif in other visual ways.
If you choose to use vignetting in your digital video project make sure that you only do that in post-production in a non-linear editing system that will facilitate such a video effect. This is going to end up looking much cleaner in its appropriation of vignetting, mainly because you can usually decide exactly how much bright and dark you want.
Make this appropriate to the image you have framed, and if you are planning on using the vignetting video effect in post-production you may want to think about this while in production so your images come out with this in mind.