Передача перспективы и фокусные расстояния

Summary

The video discusses how changing the focal length of a lens impacts the perspective and scale of objects in a photo. It explains that while a longer focal length narrows the angle of view and makes objects appear larger, perspective itself depends only on the shooting distance, not the lens. To demonstrate, the host takes photos of the same objects at the same distances using lenses of 85mm, 35mm, and 14mm, showing that when cropped equally, the perspective remains identical across focal lengths. He concludes that wide angle lenses don’t actually exaggerate perspective; rather, getting physically closer to objects emphasizes perspective foreshortening effects.

Takeaways

• 📸 Different focal lengths in lenses change the angle of view and how much of the scene is captured, affecting the perceived distance and size of objects in the frame.
• 🔍 Longer focal length lenses produce a narrower field of view, making objects appear closer and larger, emphasizing detail.
• 🟡 Wide-angle lenses, with shorter focal lengths, give a sense of greater distance from objects, capturing more of the scene in a single frame.
• 🤔 The 'normal' range of lenses closely mimics human vision in terms of scale and perspective, providing a natural-looking image.
• 👁‍🗨 Depth of field varies with focal length at the same aperture and distance to subject: shorter focal lengths yield deeper depth of field, while longer focal lengths result in shallower depth.
• 📌 Perspective is not directly affected by focal length but by the distance between the camera and the subject; changing lenses doesn't alter perspective if the shooting position remains constant.
• 👀 Using different focal lengths from the same shooting spot to capture the same subject shows that proportions and perspective remain unchanged, despite variations in composition.
• 🎬 Crop tests with images taken at different focal lengths demonstrate that perspective and proportions do not change with focal length but with camera-subject distance.
• 🗣 Debunking a common myth: wide-angle lenses do not inherently distort perspective nor do telephoto lenses 'compress' it; these effects are related to camera-to-subject distance.
• 📚 Practical examples and experiments in the video illustrate how perspective and scale perceptions are influenced more by physical distance than by the choice of lens.

Q & A

What is the effect of using lenses with different focal lengths on the angle of view?

Lenses with different focal lengths change the angle of view. A longer focal length lens results in a narrower angle, making objects appear closer in the frame. Conversely, a shorter focal length lens, like a wide-angle lens, provides a wider angle of view, making objects appear farther away.

How does the focal length of a lens affect the scale and perceived distance of objects in a photograph?

The focal length of a lens alters the scale and perceived distance of objects. A longer focal length brings objects closer, making them appear larger in the frame, while a shorter focal length makes objects appear smaller and more distant, even though the physical distance from the camera to the subject remains unchanged.

What is the relationship between lens focal length and depth of field at a given aperture?

The depth of field varies with lens focal length at a constant aperture. Shorter focal lengths tend to have a greater depth of field, meaning more of the scene is in focus. Longer focal lengths result in a shallower depth of field, focusing more narrowly on the subject and blurring the background and foreground.

Does perspective change with different focal lengths?

Perspective in a photograph does not inherently change with different focal lengths. It is determined by the distance from the camera to the subject. Changes in perspective often attributed to focal length are actually due to the photographer changing their position relative to the subject when using different lenses.

What happens to the appearance of a subject when photographed with a long focal length lens compared to a short one?

When photographed with a long focal length lens, a subject appears closer and more magnified. In contrast, using a short focal length lens, like a wide-angle, makes the subject appear farther away and smaller, with a tendency to stretch features, especially if the subject is close to the lens.

How does the choice of lens focal length influence the composition of a photograph?

Lens focal length influences composition by affecting the angle of view and depth of field. A longer lens can isolate the subject by blurring the background, suitable for portraits. A wider lens captures more of the scene, ideal for landscapes or architecture, and can exaggerate spatial relationships, adding dynamism to the composition.

Can the same subject photographed at different focal lengths from the same distance have the same perspective?

Yes, if the same subject is photographed at different focal lengths from the same distance, the perspective remains the same. The apparent difference in perspective often observed in photographs taken at different focal lengths is due to the photographer changing their distance from the subject.

Why might someone perceive a change in perspective when using different focal lengths?

The perception of a change in perspective with different focal lengths is often due to a change in the photographer's position relative to the subject. For instance, a photographer might move closer with a wide-angle lens and farther away with a telephoto lens, which alters the relative sizes of objects and the spatial relationship between them.

What are 'normal' lenses and how do they compare to human vision?

'Normal' lenses have a focal length approximately equal to the diagonal of the camera's sensor, typically around 50mm for full-frame cameras. They produce images with a perspective and scale similar to human vision, providing a natural look without significant distortion.

How does the use of different focal lengths affect the cropping of an image?

Using different focal lengths affects the amount of the scene captured in the frame, requiring cropping to achieve similar compositions. A longer focal length captures a narrower view, potentially needing less cropping for close-up images, while a wider lens captures more of the scene, often requiring cropping to match the composition of a longer lens.