In the Lens Effects area, we can add several lens effects directly to the rendered image and see the results almost in real time. Depending on the complexity of the scene and the available resources for your computer, it may take a few moments for the rendered scene to get updated with the effects. All the effects that are grouped in the lens effects area are related to real distortions of optical events that really occur in photography and cinema.
Choosing those effects will result in some interesting changes in the image, which will make our render look like a shot taken by a photographer. We only have to take care of the amount of effects added to a single image because even in LuxRender, these effects can take a long time to compute and slow down the refinement process. In some cases, it may even be the reason for a crash on the computer. It's a good practice to save the project every time a lens effect is applied to avoid any loss of data.