----- Original Message -----
From: "ADavidhazy" <andpph@xxxxxxx>
To: "List for Photo/Imaging Educators - Professionals - Students"
<photoforum@xxxxxxxxxxxxxxxxxx>
Sent: Monday, January 17, 2011 12:12 AM
Subject: Sample exam for your amusement
It is midterm exam time again and so if you'd like to see if you can
figure out answers to questions never before having beforehand heard the
answers (Reminiscent of Karnak the magnificent?) this link takes you to a
sample exam covering 5 weeks in which standards, shutter calibration,
velocity and rotation rate measurements, electronic flash concepts and
intro to time lapse and high speed imaging were discussed/ covered.
http://people.rit.edu/andpph/text-exam-sample-high-speed-2010.html
;)
Andy
1. lines = 625x50 for PAL, 525x29.97 NTSC
2. 199.999 degrees
3. 8mm or, it may remain 2mm and the speed of the shutter may reduced to
1/4
4. travel velocity | aperture in the film gate
5. the camera OR the light source could be moved a known distance at a known
velocity, a set distance between the source and capture and the resulting
image examined for the pulse 'rate' per mm of sensor/film
6. velocity = distance covered x time
7. as the film/sensor is not wholey exposed at once but rather by a
progressive exposure, perspective changes as the shutter passes across the
film/sensor, and moverment of the subject will result in change relative to
earlier or later exposures of the subject causing he subject image
distortion.
8. the start and end points of the movement period must be known to
determine distance covered, if the distance recorded excedes the frame then
the total distance covered cannot be determined.
9. a moving subject will only reflect light from it's position for the
duration of time it remains stationary (or crosses a portion of the image
area)
10. a the 1x1 foot subject produces a 1 foot x 2 foot image at 100 feet per
second, so the oject has moved 1 foot in at 100 fps, velocity = 100fps
11. a moving car
12. gravity effects objects such that they accelerate at 9.8m/s
13. 1000fps/ 100 = 10 feet
14. I see 4.5 revolutions in a 0.25 second exposure.. so 4.5 x 4 = 18 rps or
1080 rpm
15. Assuming the scale indicates that each box on the side represents 1
inch: the seed is descending at 20 inches/ second
16. 0.000001 = 1/1000,000
17. independant = true. rotation is not related to distance, rotation is
relative only to the subjects orientation and time period.
18. True if applicable to linear motion, as the field of view is increased
with shorter focal length lenses - so the distance traveled across the FoV
is effectively smaller, there fore less 'motion' is recorded.
19. current and resistance.
20. the size of the circles of confusion
21. reknown for his invention of and work with electronic strobes and
flashes.
22. 340m/s
23. duration and light output are reduced
24. increase in blue / UV output of the flash
25 1/1100 second delay
26. I've heard two differing takes on this: effecive flash duration = time
from 1/2 of the maximum power rising to 1/2 power falling, the other is the
time from 1/3 maximum power to 1/3 falling power. 'standards' are funny
things ;)
27. the residual flash continues to expose the projectile as the power of
the flash declines, reducing
illumination on the forward moving projectile.
28. an intervalometer counts time periods, used in photography it can
triggers devices and these timed intervals.
29. 20 seconds at 30 fps = 600 frames. 720 minutes to record, so 720/600 =
one frame per 1.2 minutes (72 seconds)
30 xxx
31. xxx
32. arguably invented motion picture, proved a galloping horses feet are all
off the ground at some point during the horses stride. Upset people..
33. high frame rate, high resolution, high exposure capability.
34. my guess is resolution.
35. sensing a trick question.. A Mb is either 1 000 000 bytes or 1048576
bytes , a gigabyte is either 1 000 000 000 bytes or 1 073 741 824 bytes. to
complicate this, a drive has a file allocation table, FAT, FAT12, FAT 6,
FAT32 or NTSC although generally memory storage cards are FAT,
FAT 16 or FAT 32. Each file allocation table type will eat into the actual
storage capacity of the drive, and each will use more or less space to store
data in clusters of differing sizes. So for example with one FAT type, if a
file is under 32 bytes, it will occupy 32 bytes on the drive, if over
between 32-64 bytes it will occupy a full 64 bytes on the disk. If a 1Mb
file of an arguable size falls on the grey edges of a FAT type it will
occupy more or less than either of the standard interpretations of what a
megabyte is and will use more or less space on this theoretical disk and
increase or reduce the number that can be stored. .. that's as close as I
get to an answer without more clarity in the question ! ;)
36. a rotaing prism to act as the both a shutter and a mirror to expose the
film
37 xx
38 going for f4+ 1/2 stop for that one!
/confesses looking up the numbers for 35, I can never remember the exact
numbers!
