Obj 1.8 – Test the design
1) Exposure Time Calculations
2) User Instructions
3) Picture
We’ve built cameras;
now let’s test them!
What do we need to do to test the cameras?
Take camera and film paper into
darkroom
Open camera
Insert film paper into
camera
Close camera
Carry camera to photo
location
Set camera up and align with subject
Open aperture;
start timer Wait for time Close aperture
Carry camera to darkroom
Open camera Remove film
Take camera from darkroom
and store
Exposure Time Calculation
F-number = focal length/pinhole diameter
The table below shows exposure time based on F-number. Find the F-number value closest to your camera’s F-number in the first row.
Find the exposure time in seconds in the second row.
--OR--
The above numbers assume it is a sunny day. For an overcast day, x2 your exposure time. For a cloudy day, x4 your exposure time.
F# 16 22 32 44 64 88 128 176 256 352 512 704 …
Sec 0.1 0.2 0.4 0.8 1.6 3.2 6.4 12.8 25.6 51.2 102.4 208.8 …
Object Distance Film Placement Exposure Time Picture
You built your camera with a particular film
placement (2-8”) that depended on the object’s distance (5-20’).
We are going to approximate the 10x10’ mural by taking a picture of a car in the parking lot.
Make sure the sun is at your back.
Exposure Time Calculations
Object Distance (ft) Film Place2ment
(i4n) F# Exposure Time (s)
5 2
10 4
15 6
20 8
User Instructions
You need to come up with a procedure for how to operate your camera.
Write down step by step instructions so that your user knows how to operate your camera.
User Action flow chart will help.
Discussion
Assuming that your first test picture was not perfect, why not?
What are you going to do to fix it?
Why do engineers generally have to test and refine
over several cycles?
Steps of the
Engineering Design Process
1)
Receive the Design Challenge
2)
Analyze User Needs
3)
Analyze Product Functions
4)
Generate design Concepts
5)
Select a design
6)
Build the design
7)
Test the design
…
8)
Refine the design
I will collect your 1.8 notes to check for the following:
Exposure time Calculation
User Instructions
Picture
