Introduction to Engineering 181                              Problem 1

Problem 1:  In your camera lab you performed measurements on the physical aspects of the camera that related to lense placement, aperture, and focal length.  One thing you discovered is that there is a near limit to the depth of field (called sn) inside which the camera cannot properly focus.  This limit depends on the size of the aperture.  In your lab notes we find the following equation relating sn to aperture size (d) or F-stop (= k = f/d).

where, f is the focal length; s is the object distance; and u is the size of the circle of confusion.

For this problem, f = 0.033 m, s = 0.38 m, and u = 0.00005 m

Open Excel and perform the following tasks:

1)     Label one column “Constants” and input the letters f, s, and u below this heading.

2)     Label a second column “Values” and input the values of each constant next to its label.

3)     Label a third column “F-stop” and input values 5, 10, 15, 20, 25, 30, 45, 60 below this heading.

4)     Label a fourth column “Sn (m)” and input a formula to calculate this from the above equation.  Use absolute referencing for f, s, and u and relative referencing for F-stop (F-stop is k in the equation).

5)     Copy one of your formulas to a blank cell and remove the “=” sign so that the formula is displayed.

6)     Select the data for F-stop and Sn then use the chart wizard to produce an X-Y Scatter plot.  Be sure to incorporate a title and axis labels.

7)     Select the data points and insert a linear trendline, making sure to display the equation on the chart.

8)     Place the chart close to the data (below it) and print out your results showing the calculations and plot (on a single page if possible).

(34%)                             TA:                                                                                  WI01

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