Key Concepts:
* Perspective: Perspective is how objects appear smaller the further away they are. Focal length exaggerates or compresses this effect.
* Compression: Compression refers to how much a longer focal length visually brings distant objects closer together. It makes the background appear larger and closer to the subject.
* Distortion: Distortion is the alteration of the apparent shape of objects. Wider focal lengths can cause distortion, especially near the edges of the frame.
How Different Focal Lengths Affect the Face:
* Wide-Angle Lenses (e.g., 16mm-35mm):
* Pros: Can capture a broader scene, including the environment around the subject. Can create a dramatic, documentary-style portrait.
* Cons:
* Distortion: Exaggerates features closest to the lens, making the nose appear larger and the ears smaller and further back.
* Perspective Issues: Can make the face look stretched or warped, especially towards the edges of the frame. The forehead can appear disproportionately large.
* Less Flattering: Generally not recommended for traditional portraiture due to the unflattering distortion.
* Best Used For: Environmental portraits, capturing a sense of place and subject in context, or for deliberate artistic effect.
* Normal Lenses (e.g., 50mm):
* Pros: Provides a relatively natural perspective, similar to how the human eye sees the face. Good for balanced, straightforward portraits.
* Cons: Can be seen as bland or uninteresting by some. May require you to get relatively close to the subject.
* Best Used For: Simple, classic portraits where a true representation is desired. A good starting point for learning portraiture.
* Short Telephoto Lenses (e.g., 85mm):
* Pros:
* Flattering Perspective: Compresses facial features slightly, making the face appear slimmer and more refined. Nose appears smaller, features look balanced.
* Background Blur (Bokeh): Creates a pleasing background blur, isolating the subject.
* Comfortable Distance: Allows you to be far enough away from the subject to make them feel comfortable and less self-conscious.
* Cons: Can sometimes feel slightly less "real" due to the subtle compression.
* Best Used For: Classic portraiture, headshots, beauty photography. Considered by many to be the ideal portrait focal length.
* Medium Telephoto Lenses (e.g., 100mm-135mm):
* Pros: Increased compression compared to 85mm. Further flattering perspective, isolates the subject even more.
* Cons: Requires more distance from the subject. Can make the background appear very close, which may not always be desirable.
* Best Used For: More formal portraits, beauty shots, portraits in crowded environments where you need to isolate the subject.
* Long Telephoto Lenses (e.g., 200mm+):
* Pros: Extreme compression. Can bring distant backgrounds very close, creating unique visual effects.
* Cons: Requires a lot of distance. Can make the face appear very flat and two-dimensional. May lose some of the sense of connection with the subject.
* Best Used For: Wildlife photography adapted to portraiture for a unique effect, candid portraits taken from a great distance.
Important Considerations:
* Aperture: While focal length affects perspective, aperture (f-stop) controls the depth of field (how much of the image is in focus). A wider aperture (e.g., f/1.8) creates a shallow depth of field, blurring the background and further isolating the subject. This is often used in conjunction with longer focal lengths.
* Camera Position: The distance between you and the subject is crucial. Changing focal length without moving will change the *field of view* but not the perspective. To see the full effect of a focal length, you need to adjust your position to maintain the same framing.
* Subject Shape: Rounder faces often benefit from longer focal lengths to add definition, while longer, thinner faces might work well with slightly wider lenses.
* Personal Style: Ultimately, the best focal length for portraiture is a matter of personal preference and the desired aesthetic. Experiment and see what works best for you and your subjects.
In summary:
* Shorter focal lengths (wide-angle) distort the face, making the nose appear larger and features appear stretched.
* Normal focal lengths (around 50mm) provide a natural perspective.
* Longer focal lengths (telephoto) compress the face, making features appear slimmer and more refined, and creating pleasing background blur.
By understanding how focal length affects perspective and the shape of the face, you can make informed decisions to create flattering and expressive portraits.