Key Concepts:
* Perspective: This refers to the apparent relationship between objects in an image in terms of their size and distance. Focal length directly affects perspective.
* Compression: Longer focal lengths compress the perceived distance between objects in the frame, making them appear closer together. Shorter focal lengths exaggerate the perceived distance, making objects further apart.
Effects of Different Focal Lengths:
* Wide Angle Lenses (e.g., 16mm-35mm):
* Distortion: The closer you get to the subject, the more noticeable the distortion becomes. Features closest to the camera (like the nose) appear disproportionately larger, while features further away (like the ears) appear smaller.
* Exaggerated Depth: The distance between the subject and the background appears stretched.
* Less Flattering for Portraits: Usually avoided for close-up portraits because the distortion is rarely flattering. However, they can be used for environmental portraits where showing the surrounding context is important.
* Rounded face: makes the face look rounder and fatter.
* Examples: Not generally recommended for classic portraits unless a specific artistic effect is desired.
* Normal Lenses (e.g., 50mm):
* More Natural Perspective: Mimics the way the human eye sees the world in terms of perspective.
* Good Starting Point: A versatile option for portraits, providing a balanced representation of facial features.
* Minimal Distortion: Less distortion than wider lenses, resulting in a more accurate representation of the face.
* Can Require Getting Close: To fill the frame with the subject's face, you'll need to be relatively close, which can feel a bit intrusive for some subjects.
* Short Telephoto Lenses (e.g., 85mm):
* Considered a Classic Portrait Lens: Often cited as a very flattering focal length for portraits.
* Slight Compression: Slightly compresses the distance between features, which can be subtle and pleasing.
* More Background Blur (Bokeh): Creates a shallower depth of field, blurring the background and isolating the subject.
* Flattering for Most Face Shapes: Generally flattering, providing a balanced and appealing representation.
* Reduces apparent nose size: The compression effect tends to minimize the perceived size of the nose.
* Medium Telephoto Lenses (e.g., 100mm-135mm):
* Increased Compression: Further compresses the perspective, minimizing the perceived distance between features.
* Stronger Background Blur: Creates a more pronounced background blur, further isolating the subject.
* Still Flattering: Generally produces flattering results, though too much compression can sometimes make a face look a bit "flat" if not used carefully.
* Requires More Distance: You'll need to stand further away from the subject to frame the shot.
* Long Telephoto Lenses (e.g., 200mm+):
* Significant Compression: Compresses the distance between features dramatically.
* Maximum Background Blur: Creates very shallow depth of field, blurring the background almost completely.
* Can Look Unnatural: Too much compression can flatten the face and make it look less dimensional.
* Can Flatten Features: Can make the face look wider.
* Requires Significant Distance: Requires a substantial distance between the photographer and the subject. This can be useful for capturing candid shots or when you need to be unobtrusive.
* Less Common for Close-Up Portraits: While possible, it's less common for close-up portraits because of the compression and the difficulty of communicating with the subject at a distance.
Summary Table:
| Focal Length | Perspective | Compression | Distortion | Distance to Subject | Common Use | Effect on Face Shape |
| ------------------- | ------------- | ------------- | ----------- | -------------------- | --------------------------------------------- | ------------------------------------------------------------- |
| Wide Angle (16-35mm) | Exaggerated | Decompressed | Significant | Very Close | Environmental Portraits, Specific Artistic Effects | Rounded face, Larger Nose, Distorted Proportions |
| Normal (50mm) | Natural | Minimal | Minimal | Close | Versatile Portraits | Generally Accurate Representation |
| Short Tele (85mm) | Slight | Slight | Very Little | Moderate | Classic Portraits | Flattering, Reduces Nose Size |
| Medium Tele (100-135mm) | More Compressed | More | Minimal | Further | Portraits, Isolating Subject | Still Flattering, Potential for "Flattening" with Overuse |
| Long Tele (200mm+) | High | High | Minimal | Very Far | Candid Portraits, Limited Use for Close-Ups | Can Flatten Features, Widens Face |
Other Factors to Consider:
* Camera Sensor Size: The crop factor of your camera (e.g., full-frame vs. APS-C) affects the *effective* focal length. A 50mm lens on an APS-C camera (with a crop factor of 1.5x) will have an equivalent focal length of 75mm.
* Distance to Subject: The closer you are to the subject, the more pronounced the effects of the focal length will be.
* Composition: Even with a flattering focal length, poor composition can still result in an unflattering portrait. Consider angles, posing, and lighting.
* Personal Preference: Ultimately, the best focal length for a portrait is subjective and depends on your artistic vision and the specific look you are trying to achieve.
In conclusion:
Choosing the right focal length for portraiture is about understanding how it affects perspective and how that, in turn, influences the perceived shape and proportions of the face. Experiment with different focal lengths to find what works best for your style and the particular subject you are photographing.