Chapter 25: Optical Instruments © 2016 Pearson Education, Inc.

Goals for Chapter 25 To study the camera and the projector. To see the eye as an optical instrument. To review by doing examples pertaining to magnifiers, microscopes, and telescopes. © 2016 Pearson Education, Inc.

The Camera – Figure 25.1 The shutter controls the exposure time and this depends on the film (which would be chemistry, the darkening of silver salts on exposure to light). The size of the opening provides interesting physics and is calibrated as "f-stops." © 2016 Pearson Education, Inc.

Using the f-Stop – Figure 25.3 This problem shows us the physics behind what photographers refer to as "depth of field." Refer to Example 25.1. © 2016 Pearson Education, Inc.

The Digital Camera – Figure 25.4 The digital camera is an elegant triumph of engineering. The photodiode shown next to the quarter serves as the film. The challenge was to bring a diode array to a density that rivaled the clarity of film photography. New digital cameras with megapixel resolution can do this. © 2016 Pearson Education, Inc.

A Better Diode Array Already Found in Nature? The insect eye shown on page 807 rivals or exceeds any digital camera or projector yet produced. © 2016 Pearson Education, Inc.

The Eye – Figure 25.5 The physics of eyeball optics and the chemistry of rhodopsin's conformational changes to produce sight is a masterpiece of design and function. © 2016 Pearson Education, Inc.

Aging Changes the Focal Point of an Eye – Table 25.1 © 2016 Pearson Education, Inc.

Overview of Defects in Vision – Figure 25.6 More often than not, myopia is a problem for younger patients. Myopia is difficulty bringing distant objects into focus. Again more often than not, hyperopia is a problem for older patients. Hyperopia is difficulty bringing objects close to the eye into focus. © 2016 Pearson Education, Inc.

Astigmatism – Figure 25.7 Astigmatism is a uniformity of image issue. In common terms, myopic and hyperoptic vision is an issue of near and far. Astigmatism is side to side. © 2016 Pearson Education, Inc.

Hyperoptic Correction – Figure 25.8 As you get older, you may find that reading the yellow pages has you holding the book far enough away from your face that it is difficult to hold it still. The correction is magnification. © 2016 Pearson Education, Inc.

Myopic Correction – Figure 25.9 You may remember squinting to see the blackboard in grade school (changing depth of field). Glasses, followed by contacts, finally corrected with LASIK can fix the problem by using diverging lenses to bring the focus from the middle of the eye to the retina. © 2016 Pearson Education, Inc.

Quantitative Hyperoptic Correction – Figure 25.10 Refer to Example 25.2 on page 810. © 2016 Pearson Education, Inc.

The Magnifier – Figure 25.14 Taking advantage of a converging lens, position relative to the object and angular size, visual perception of an object is magnified. Refer to Conceptual Analysis 25.1 and Example 25.5. © 2016 Pearson Education, Inc.

The Microscope – Figure 25.13 Refer to Conceptual Analysis 25.2 and Example 25.5. © 2016 Pearson Education, Inc.

The Telescope – Figure 25.14 Taking advantage of a converging lens, position relative to the object and angular size, visual perception of an object is magnified just like the microscope, changing only order of optics. Refer to Conceptual Analysis 25.3. © 2016 Pearson Education, Inc.

Reflecting Telescopes – Figure 25.16 Using mirrors rather than lenses, optical aberrations may be avoided. The Hubble Space Telescope is this type of instrument. © 2016 Pearson Education, Inc.