Key Principles:
* Wider Focal Lengths (e.g., 24mm, 35mm): Exaggerate perspective.
* Longer Focal Lengths (e.g., 85mm, 135mm, 200mm): Compress perspective.
How Focal Length Affects Specific Features:
* Nose:
* Wide Angle: Makes the nose appear larger and more prominent relative to other features, especially if the subject is close to the camera. This is because the nose is physically closer to the camera than other features, and wide angles exaggerate the relative distances of objects in the frame.
* Long/Telephoto: Makes the nose appear smaller and less prominent, as the compression effect reduces the perceived distance between the nose and the rest of the face.
* Eyes:
* Wide Angle: Eyes might seem wider and further apart, especially if the subject is close. Can distort the eye shape slightly, making them appear more bulging.
* Long/Telephoto: Eyes appear closer together and more naturally proportioned.
* Cheeks and Jawline:
* Wide Angle: Can make the cheeks appear rounder and the jawline softer due to the distortion.
* Long/Telephoto: Tends to slim the face and define the jawline more, as the compression minimizes the roundness.
* Ears:
* Wide Angle: Can make ears appear slightly further back and less prominent.
* Long/Telephoto: The ears appear closer to the side of the face and are less likely to be noticeably de-emphasized.
* Background:
* Wide Angle: Shows more of the background. This can be great for environmental portraits but can also be distracting if the background isn't carefully chosen. Background elements appear larger and closer than they are in reality.
* Long/Telephoto: Compresses the background, making it appear closer to the subject and blurring it more intensely. This helps isolate the subject and create a shallow depth of field.
Ideal Focal Lengths for Portraiture (and Why):
* 50mm (The "Standard" or "Nifty Fifty"): A good starting point. It offers a perspective close to how the human eye sees things. Minimal distortion, but might not be the most flattering for everyone.
* 85mm: Considered by many to be a sweet spot for portraits. Provides pleasing compression, flattering facial features, and good subject isolation (blurred background). Requires more distance from the subject.
* 100mm - 135mm: Even more compression than 85mm, further blurring the background. Great for tight headshots or portraits where you want to emphasize specific features without distortion. Requires even more distance from the subject.
* 24mm - 35mm (Wide Angle): Generally avoided for traditional portraits unless you're going for a specific effect (e.g., an environmental portrait showing a lot of the surroundings or a dramatic, exaggerated look). Requires careful posing and awareness of distortion.
Practical Considerations:
* Distance: The focal length you choose dictates how far you need to be from your subject. Wide angles require you to be close, while telephoto lenses require significant distance. Your working space will be a factor.
* Aperture: Longer focal lengths often pair well with wider apertures (smaller f-number like f/2.8 or f/1.8) to create that beautiful shallow depth of field (bokeh) that blurs the background and isolates the subject.
* Communication: Being physically closer (with a wide-angle lens) allows for easier communication with your subject, which can be crucial for directing their pose and expression.
In summary:
The choice of focal length is a creative decision that directly impacts the final look of your portrait. Experimenting with different focal lengths is the best way to understand how they affect your subjects and to develop your own personal style. Consider the subject's features, the desired look, and the environment when making your choice.