Object size indicated by the reflected image: | |
Wedding Cake -
metal balls reflected images of "Carriage house" |
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1.[Carriage house image] on spherical diameter is about
28%. According imaging principle for spherical mirrors, the
angle(θ) from front corners of the carriage house to the
nearest metal ball is 66°. {When object distance >> ball radius, imaging
proportion: sin(θ/4)=0.28
, then θ=66°} Inside the carriage house is 7.6 meters wide, about 1.75 meters long is the eave extend outside the wall, together with the stairwell (on the left side of the house), the tailgate (house's right side) & trees around the house, so the width of Carriage house's image should at least be 11 m = Roof span. [(Shooting time11:30 10/22/1980), counting the shadows of the house & trees, the dark image will be more than 13m.] [#800] (The lower right corner of the residence to a tangent of the low rock wall) + (the 2nd floor window to the eave corner at the middle of Roof), two white lines intersect - the camera location (in the carriage house, not against the "removable wall"). Drawing two tangent lines from the shot to the ship, get the range of the ship and the bisector. Drawing a 66° angle from both sides of the carriage house to the bisector, get the nearest metal ball distance 8.6 meters from the carriage house. At this location for Rings & Hull can be presented on the photo, the ship's diameter (plus its edge) should at least be 6.5 meters. 2.Compared with [#801],
[#802]: the ship in these photos are located in the
same place. [Shot positions (a,b,c) shown in fig.1, Carriage house.] |
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* Depth of Field is determined by three factors - aperture size, the focal length, and distance from the lens... It is the only way to determine the size by backward-reasoning on spherical mirror images. | |
Slander site - http://www.tjresearch.info/Wedcake.htm -- [Custom lid - no screw thread] |