Reference: https://www.compadre.org/Physlets/optics/ex36_1.cfm

1/do + 1/dj = 1/f m = hi/ho = -di/do f-stop = f / D https://www.compadre.org/Physlets/optics/ex36 1.cfm Open the link. Click on Normal Lens. We see an iris, lens and film. Click on Object Source. We start with distances, from object to lens, and from lens to film (subtract x coordinates to get these). Coordinates: object x = 2.3, height h. = 1.2, lens x = 5, film x = 5.75. Use From do and di, calculate m = - (2 sig these coordinates in 1b and 2all, subtracting as needed to get do and di. figs). Questions 1-3 concern an object, lens and possible image. Exploration 36.1: Camera The object is focused on the film (image plane) of the camera if its rays on the image side, converge on the film's surface. They don't in 1, then Film barely do in 2. Then we move lens and object in 3, so this happens. So it's in 2 and 3 that you can measure di and f, and do the lens equation. 1.a. Is the object focused on the film? Yes/No. 1.b. do = . di = _can't. Is it valid to calculate f? Yes/No. 2.a. Grab and move the object all the way to the left, to x = 0. 0 Now the image moves to the left, to "barely" reach the film. The film is also called the image plane, for a camera. 0.71, 4.97 Add/Remove: Far Source | Near Source | Object Source Measure do = di = Calculate f = (3 sig figs). Normal Lens | Telephoto Lens | Wide-Angle Lena 2.b. Measure ho = _ Measure hi = -_ From ho and hi, calculate m = (2 sig figs). 2.c. Measure the diameter of the iris (yellow aperture), D = . Calculate the f#, f- (2 sig figs). Move the object closer to the lens, so its head has coordinate (2, 1). It focuses well-behind the film. This means we need to move the lens further away from the film. Exploration 36.11 Camera Do this by pulling it to the left, so that it butts up to the iris (see figure here). Then move the object horizontally so it focuses on the film, as shown. Double check the object's height, that its y coordinate is hi = 1.0. 3.a. Measure do = . di =_ . Calculate f = (2 sig figs). From do and di, calculate m = (2 sig figs). 3.b. Measure ho = Measure hi = -_ From ho and hi, calculate m = _(2 sig figs)