Understanding the role of aperture in photography reveals that it is often not the most efficient way to control exposure in a scene. Despite being a part of the ‘exposure triangle,’ aperture settings are typically best when left constant, with adjustments to shutter speed, ISO, or external lighting methods preferred for exposure control.
Why Keep Aperture Constant?
Often, it’s advisable to select a bright aperture and maintain it. This approach aligns with the views of renowned cinematographers, such as the one who shot “The French Connection,” who advocated for using lenses at wider apertures. A prime example is the RF 28-70mm f/2 zoom lens, which is sharp and performs optimally at its maximum aperture. The significance of wide apertures becomes more evident when considering that many lens aberrations noticeable on digital sensors were less prominent in film photography.
Changing Aperture: Creative Reasons
While adjusting aperture for exposure is not recommended, there are several creative scenarios where modifying it is beneficial:
- Adjusting for Distance Changes：Change the aperture when the distance to the subject varies significantly.
- Selective Focus: Employ selective focus to draw attention to a specific element amidst numerous others.
- Uniform Look Across Focal Lengths: Adjust aperture to maintain a consistent aesthetic when switching between different focal lengths.
- Enhancing Detail: Stopping down the lens can increase sharpness, but it primarily reduces aberrations and expands the depth of field, thereby enhancing image contrast and including more of the scene in focus.
- Managing Lens Aberrations: Aperture adjustments can help control various lens aberrations, including flares, blooming, chromatic aberration, vignetting, contrast, and the shape of bokeh balls.
- Evoking Emotion: The inherent characteristics of lenses, such as their bokeh or flare, can evoke specific emotions in photography.
The Bottom Line
Mastering aperture use is primarily a professional consideration, but it’s an essential technique for anyone serious about photography and videography. Understanding when and why to adjust aperture, rather than relying on it for exposure control, can significantly enhance the artistic quality of your work.
