CS178 Assignment 8 - Portraits and Light
A studio-lit portrait of Andrew. Photo by Elena Adams.
People are certainly one of the most interesting and
most challenging subjects to photograph. For this last
assignment, you'll be using all of the skills you've
learned during the course to take some stunning
portraits. You will need to think about lighting,
backgrounds, depth of field, composition, and color. You
can also (tastefully) touch up each photo in Photoshop. By
now these skills should come quite naturally to you, so
you can focus your creative effort on capturing something
truly unique or special about your portrait subject.
If you find yourself without anyone willing to model
for you this week, you can take a self-portrait for any of
the requirements. This is an interesting type of
photograph in its own right, and adds a degree of
Like last week, there are also a set of exam-style
questions at the end of this assignment. Although we will
not grade these, they will exercise your understanding of
photographic lighting and help you to prepare for the
final exam. The answers to these questions will be posted
on Wednesday, Jun 6 after the assigment is due.
This week there are five photographic requirements.
Requirements 1 through 4 must be met by taking pictures
of human beings. (Sorry, no portraits of pets, stuffed
animals, etc. this week!) Requirement 5 can be met
using any subject of your choosing.
- Requirement 1: Indoor Traditional
Take a portrait of someone using a
traditional portait lighting setup as described in
lectures (a key light, a fill light, and possibly a
background light and accent/rim light). Unless you
have some fancy lighting gear of your own, you should
take this picture during your regular section meeting
where we will set up a full studio lighting kit.
- Requirement 2: Indoor Natural Light
Take a portrait of someone indoors
using only non-electric sources of light (a fireplace,
candles, the sun, etc). You might want to arrange
someone near a window. Think about the light in the
same way as for the studio lighting, and comment on
how you created a fill light, how you created a key
- Requirement 3: Outdoor Available Light
Take a portrait of someone outdoors
under available lighting only. Comment on what serves
as the fill light and key light. If you like, you can
also make this one a candid shot, in which the subject
is not aware you're taking a photo (or at least
appears to not be aware).
- Requirement 4: Flash + Ambient
portrait which uses a combination of your camera's
flash and ambient illumination. Again, comment on what
serves as the key light and what serves as the fill
light. Remember, you need not point the flash right at
the subject - with a small hand-held mirror or white
card you can bounce any camera's flash elsewhere.
- Requirement 5: Non-photorealistic
Photograph This requirement is unrelated to
portraiture, but we thought it would be fun now that
you are all experts at image editing. Use a single
photograph or combination of photographs to create a
single, non-photorealistic image in Photoshop. This
requirement is wide open to your creative
interpretation, but result must look substantially
non-realistic in some way. As a hint: you may want to
try taking photographs under multiple different
lighting conditions (e.g. at different times of day &
night, or flash/no flash with unusual processing); or
you may try stitching together pictures of your
subject from multiple viewpoints. You may find some
inspiration in the artwork
or the photographic works
Upload your photos and add comments. Upload your photos
using the Picasa account you created in the first week to a public
Picasa album titled "CS178 Assignment 8 - Portraiture". Write at
least two short paragraphs (ie two picasa comments) below each of your
photos explaining how you arranged the scene, how you took the photo,
what relevant camera settings you used and why, any image processing
done to the photograph afterwards, and most importantly, which
requirement the photo covers.
As usual, we've posted an
solution to this assignment to let you know what we expect. For
additional inspiration, you may want to peruse the best CS178
photographs (as selected by the TA's and instructor)
, and 2011.
However, you do not need to meet the assignment requirements in the same way as
these solutions do - in fact, you should challenge yourself to come up
with creative, unique compositions. There are plenty of possibilities
out there. Surprise us!
Please remember that the photographs that you submit for each
assignment must be taken by you specifically for this course. Do not
reuse old photographs that you may have laying around, even if they
perfectly meet one of the requirements!
If you have questions or comments about the photos we used in the
example solution, feel free to add them as comments below the
corresponding photograph in Picasa Web, or to email us.
These questions are for your own educational benefit; you do not need
to submit your answers. After the assignment is due we
will select the correct answers in bold. This is the last set of practice
problems (besides Final Review) that we will give out before Finals, so
please make sure to do these problems on your own.
- Problem 1a.Betelgeuse is the second brightest star in the constellation Orion (it's Orion's right shoulder). The surface of Betelgeuse has a temperature of about 3500 Kelvin (5840 Farenheit), and for this question you should assume stars are perfect blackbody radiators. If you were to take a photograph of Betelgeuse with your white balance set to daylight (6500 Kelvin), what color would Betelgeuse be in the photo?
- a) Reddish
- b) Greenish
- c) Blueish
- d) Whitish
- Problem 1b. What color would Betelgeuse appear if you instead set the white balance to tungsten (3200 Kelvin)?
- a) Very red
- b) Slightly red
- c) Slightly blue
- d) Very blue
- Problem 2a. As every scout knows, you can start a fire on a sunny day by focusing the sun's image on a piece of paper placed on the ground. ---------(Warning: If you rush out to test this, be careful! Never look at the sun directly, never hold a magnifying glass between your eye and the sun, and never look directly at its focused spot on a white surface. Sunglasses are not enough to protect you from doing any of these things. Glacier goggles or welder's helmets are sufficient for brief glances at the white surface, but not at the sun.) Is the luminance of the sun as seen from the focal point of the lens (where the light rays converge, at the piece of paper) more, less, or the same as the luminance as seen from same point in the absence of the magnifying glass? Select the correct choice:
- a) more than
- b) less than
- c) the same
- Problem 2b. Is the luminous intensity at the focal point more, less, or the same as the luminous intensity at the same point in the absence of the magnifying glass? Select the correct choice.
- a) more than
- b) less than
- c) the same
- Problem 2c. Is the total luminous power (in lumens) reaching the entire piece of paper more, less, or the same as the power reaching the paper in the absence of the magnifying glass? Select the correct choice. Assume the piece of paper is much larger than the magnifying glass.
- a) more than
- b) less than
- c) the same
- Problem 3. True or False: You can think of a diffuse (or Lambertian) surface as being made of a bunch of tiny reflectors, all basically lying flat across the surface of the object.
- Problem 4. True or False: To verify the claim that, on a sunny day with a blue sky, shadowed areas should be about 1/5 as bright as non-shadowed areas, you can take a JPEG image and measure the ratio of pixel values in those two areas.
- Problem 5. Simple demosaicing algorithms based on linear inter\
polation are likely to fail on which of the following scene subjects? Circle a\
ll that apply.
- (a) A bright orangewall
- (b) A picket fence 50 feet away
- (c) A fabric with thin stripes on it
- (d) A transclucent green vase
- (e) None of the above scenes will cause problems.
- Problem 6.If a spotlight has a uniform radiant intensity of 10 W/sr over its whole cone of light, and the cone subtends 2 steradians, how much total power will fall on a large white wall 10 meters away when the spotlight is pointed at it? Assume the wall is larger than the lit area created by the spotlight. Circle the best answer.
- a) 5W
- b) 10W
- c) 20W
- d) 40W
- Problem 7.If you want to bring out the most detail in a rough surface, you should light it with (circle the best answer):
- a) grazing light
- b) direct light
- c) spotlight
- d) diffuse light
We will assign grades based on whether you met the
requirements of the assignment. For each requirement, you'll be given
a check for meeting the requirement, check-minus for not quite meeting
the requirement, or check-plus if you do something spectacular that
makes your grader's jaw drop.
11:59PM, Wednesday, June 6, 2012
Please Note: We will accept no late assignments or replacement photos after
midnight on Sunday June 10. Be sure to read the lateness policy from
outline, or contact your TA if you have any questions.
Marc Levoy, Andrew Adams, and Jesse Levinson