Transcript
Page 1: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

Photography Lesson 2

Pinhole Camera

Lenses

Page 2: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

The Pinhole Camera

Page 3: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• as light strikes an object, it is reflected, scattered in all directions

Page 4: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• here we see the light that is scattered from a single point on this apple. the light travels in virtually every direction simultaneously, and strikes a flat surface multiple times

Page 5: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• here we see the light that is scattered from a single point on this apple. the light travels in virtually every direction simultaneously, and strikes a flat surface multiple times

Page 6: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• Imagine that there is a wall with a tiny opening in it between the apple and a reflective surface. Only the light that is traveling in a straight line from one particular point on the apple will pass through the opening.

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• if we follow the path of light from any other point on this apple, the same result occurs

Page 8: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• if we follow the path of light from any other point on this apple, the same result occurs

Page 9: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• if we follow the path of light from any other point on this apple, the same result occurs

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• every point on the apple will reflect light that will travel in a straight line through the aperture. The light from each of these points forms an inverted image on any surface opposite the aperture.

Page 11: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• every point on the apple will reflect light that will travel in a straight line through the aperture. The light from each of these points forms an inverted image on any surface opposite the aperture.

Page 12: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• when the back wall is enclosed in a darkened chamber, this simple design is known as a pinhole camera. Typically, light sensitive film would be placed against the back wall.

Page 13: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• when the back wall is enclosed in a darkened chamber, this simple design is known as a pinhole camera. Typically, light sensitive film would be placed against the back wall.

Page 14: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• Pinhole cameras require very small apertures that are typically made with a pin-prick. As light passes through the small aperture, it produces a small, accurate circle of colored light.

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• Pinhole cameras characteristically let very little light in through their small openings, and therefore must compensate with relatively longer exposures.

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• A larger opening on a pinhole camera would not produce satisfactory results. The light that enters a larger opening spreads out before it hits the surface of the film.

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• Soft, overlapping circles result, producing an out of focus image. While the exposure time will certainly be lessened, this comes at the expense of focus.

Page 18: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• a Lens solves both of these issues, allowing sharper focus and shorter exposure time.

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The Lens

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From Pinhole to Lens

• A pinhole, as small as it is actually admits a cluster of light rays. Coming at slightly different angles, these rays continue through the hole in slightly different directions.

• A Lens creates a sharp image with relatively short exposure. To get sharp pictures, the image of a tiny point should also be a tiny point

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• The most important way lenses differ is in their focal length.

• Technically, focal length is the distance between the lens’s rear nodal point and the focal plane when the lens is focused at infinity.

• Focal length controls magnification, the size of the image formed by the lens. The longer the lens, the greater the size of objects in the image.

• Focal length also controls the angle of view, the amount of the scene shown on a given size of film

Page 22: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

• Normal-focal-length lens, also called a standard-focal-length lens, approximates the impression human vision gives. - faster

• Long-focal-length lens provides greater image magnification and a narrower angle of view than a normal lens. Long lenses are excellent when you can not or do not want to get close to the subject. – slower

• A short-focal-length lens increases the angle of view and shows more of a scene than a normal lens used from the same position. – wide angle lens

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Zoom Lens• Zoom lenses are popular because

they combine a range of focal lengths into one lens.

• Using a 28 – 105mm zoom is like having a 28mm, 50mm, 85mm, and 105mm lens instantly available, plus any focal length in between.

• Zoom lenses tend to be a little bit heavier, more expensive, and bulkier.

• Zoom lenses are best used where light is ample because they have a relatively small maximum aperture.

• Zooms that keep the same aperture at all focal lengths are complex designs and therefore relatively expensive.

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Macro

• A macro lens is useful for extremely close shots

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Page 26: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

Fisheye

• For the widest of wide-angle views, consider the fisheye lens.

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Page 28: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera
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Focus and Depth of Field

• As we’ve discussed, You can use the aperture to control the depth of field.

• There are two other ways to control or adjust your depth of field.– Focal length– Distance from the subject.

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Again, the smaller the aperture, the greater the depth of field.

same focal length, staying at the same distance

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• The shorter the focal length of the lens, the greater the depth of field.

• Same aperture, set at same distance

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• The greater the distance from the subject, the greater the depth of field.

• The pic on the left was taken at 3ft, the pic on the right, from the same lens and focal length with same aperture from 10ft farther away.

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• Why does a lens of longer focal length produce less depth of field than a shorter lens used at the same f-stop?

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Page 35: Photography Lesson 2 Pinhole Camera Lenses. The Pinhole Camera

Equivalent Exposure


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