Chapter 3
Figure 3-1, a single object is easy to focus on
Figure3-2, a resolution chart's black and white lines getting thinner and closer together
Figure 3-3a, focusing on the muzzle ensures the muzzle is in focus
Figure 3-3b, the stock of Figure 3-3a is out of focus
Figure 3-4a, zone focusing ensures everything is in focus
Figure 3-4b, the stock of Figure 3-4a is in focus
Figure 3-5, when both ends of a long object are the same distance from the photographer it is easy to have everything in focus, courtesy of I. Walker, GWU MS student
Figure 3-6, a macro lens
Figure 3-7, the macro lens pre-focused at 1:1, so that an item of evidence the size of a fingerprint will fill the frame
Figure 3-8, 1:1 magnification ratio
Figure 3-9, 1:2 magnification ratio
Figure 3-10, 1:3 magnification ratio
Figure 3-11, focused on infinity: ∞
Figure 3-12, the pairs of numbers on either side of the orange focusing line are the Depth of Field Scale
Figure 3-13, the infinity distance aligned with the right ‘22’
Figure 3-14, when infinity is not in the background, Zone Focusing should be done
Figure 3-15, when infinity is not in the background, Zone Focusing is called for.
Figures 3-16a, b, c, d, and e, notice the locations of the five pens as viewed from the top to the bottom of each image.
Figure 3-17a, DOF range of 5’ to 30’ with an f/22
Figure 3-17b, DOF less than 15’ with an f/22
Figure 3-17c, DOF less than 10’ with an f/22
Figure 3-17d, DOF less than 7’ with an f/22
Figure 3-18, focal lengths and their angles of view, courtesy of scamper.com
Figure 3-19, the relative sizes of a film negative and an APS-C sized digital sensor
Figure 3-20, the relative size of an APS-C digital sensor with a 33mm focal length, on the left; and an APS-C digital sensor with a 50mm focal length, on the right, courtesy of M. Hur and J. Buffington, GWU MS students
Figure 3-21, an 800mm lens, courtesy of AFOSI
Figure 3-22, a white pick-up 500’ away, photographed with a 50mm lens on the top, and a 960mm lens on the bottom
Figure 3-23, a student standing 400’ away in the center of the top image. Below left is an enlargement from the original image. Below right is an image from the same distance, taken at night, with an 800mm lens
Figure 3.24, the same double yellow lines photographed with a telephoto lens on the left, a normal lens in the center and a wide angle lens on the right, courtesy of S. Lingsch, GWU MS student
Figure 3-25, the true distance between the photographer and the building being accurately depicted by using a ‘normal’ lens, courtesy of K. Kinsie, GWU MS student
Figure 3-26, a wide angle lens makes the perceived distance between the photographer and the building seem to be further away, courtesy of K. Kinsie, GWU MS student
Figure 3-27, including the foreground in view suggests the photographer was a particular distance from the building
Figure 3-28, when the foreground is excluded it is unclear where the photographer was when the image was captured. They may have been relatively close, but using a wide angle lens
Figure 3-29a, a black talon bullet not filling the frame properly
Figure 3-29b, a black talon bullet properly filling the frame
Figure 3-30a, an enlargement of Figure 3-29a
Figure 3-30b, an enlargement of Figure 3-29b
Figure 3-31a, a camera without the extension tube
Figure 3-31b, adding the extension tube between the camera body and the lens results in the optical center of the lens being further from the digital sensor, which allows greater magnification
Figure 3-32, an extension tube used with a zoom lens
Figure 3-33a, a set of close-up filters
Figure 3-33b, close-up filters showing different amounts of magnification when stacked
Figure 3-34a, barrel distortion - wide angle lenses tend to have straight lines near the sides of the image bend outwards
Figure 3-34b, Photoshop can correct barrel distortion
Figure 3-35a, a building with barrel distortion because a wide angle lens was used.
Figure 3-35b, a telephoto lens causing pincushion distortion
Figure 3-35c, Photoshop can correct most distortions
