CS178 Assignment 1 - Bad Photos

Traffic Lights at the Corner of Matadero Ave and El Camino Real. Photo by Andrew Adams

Motivation

Cameras in automatic mode try to take care of the technical aspect of photography for you, and just let you frame the scene and shoot. They will attempt to make sure the scene is not too dark, not too bright, not blurry, and so on. These goals don't always match up with the photographer's intent. For this first assignment, you'll be playing with the settings on your camera to produce photos you can't easily produce in automatic mode. You'll be taking photos that your camera might consider "bad" in some technical way, but are nonetheless interesting to look at, and even artistic.

For this assignment, you'll also be setting up the online photo album that you'll use throughout the course to both submit your work for grading, and to share your work with your fellow students.

Instructions

1. Make a Picasa Web account for the course. You'll be making one new album in this account for each assignment. If you already have a google login you can use that, or you can make a new one just for CS178. Picasa web ties in with the Picasa photo management software, which you might find useful for managing your photo collection. Making a Picasa Web gallery is fairly straight-forward. If you're having trouble, come by office hours and we'll help you get started.

   The Picasa albums you make for this course should all be listed as "public" so TAs and fellow students can see the photos you've taken. If you have a particular reason to make an album not public, coordinate with your section leader to make sure he or she can still grade it.

2. Take some photos that meet the requirements listed below, and upload them as an album titled "CS178 Assignment 1 - Bad Photos", and add comments below each photo explaining 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 requirements each photo covers. See the example solution below as a guide to what we're looking for. Your comments aren't required to go into quite as much detail as the example solutions, but if you don't add comments to your photos you won't receive any credit for the assignment.

   Each photograph you upload should meet one or more of the requirements below, and you should make sure to cover every requirement with at least one photo. In other words, for each photo you upload, it should fulfill at least one requirement for the assignment, and among all of the photos you upload, every requirement should be fulfilled at least once. You should upload at least five photographs for the assignment, but no more than 10 please (or we'll never have time to look at them all!). Be sure to state in your comments (ideally right at the top) which requirements each photo meets. Note that these general rules apply to this assignment and all subsequent photo assignments in this course.

   Now, for Assignment 1 specifically: remember, even though the photos you take are supposed to be technically "bad" in some sense, we want you to create things that are interesting to look at. The "badness" should be intentional for an artistic purpose.

   • Requirement 1: At least one photo must be poorly exposed. That is, most of the image should be either very close to black (underexposed) or close to flat white to due oversaturation (overexposed).
   • Requirement 2: The main subject of at least one photograph should be motion-blurred, either due to movement of the subject or movement of the camera.
   • Requirement 3: In at least one photo, nothing at all should be in focus. It's hard to take a good looking photo where nothing is in focus - be creative!
   • Requirement 4: You should use the wrong white balance setting for some intentional effect in at least one photo. The white balance setting on a camera tells the camera what color it should expect the scene illumination to be, for example daylight (which is blueish) or indoor incandescent (which is reddish). Most cameras have an "auto white balance (AWB)" setting, and manual settings for these other illumination types. You don't need to understand white balance in detail to fulfill this requirement. It's a subject we'll cover in detail later in the course.
   • Requirement 5: At least one photo should be poorly composed. Scan through Chapter 17 of your textbook, and search on Google for "rules of composition". Read about them, and then intentionally break a few. If you're not sure what to do you may want to consider an exactly centered subject that produces an oddly symmetric photo, a confusion between the subject and a background object, or a horizon that isn't level.

3. Once you've been allocated to a section, which should happen on Thursday of the first week of class, email the web address of your picasa album to your section leader. You can find your section leader's contact details here. Send your email any time before the assignment's due date (Sunday April 8 by midnight). Note that you only have to send an e-mail for this first assignment; for subsequent assignments your section leader will already have your URL.

Example Solution

Also, 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.

Grading

It's hard to judge artistic quality, so rather than grading the individual photos, the TAs 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.

Practice Problems

To help you with exams, we are giving out practice questions at the end of each assignment. You do not have to turn in the answers for these; they are purely for your own learning benefit. The correct answers will be revealed here in bold after the assignment deadline.

• Problem 1a. True or False? If camera apertures were square instead of circular, then F numbers will be separated by factors of 2 instead of sqrt(2).
• Problem 1b. True or False? In aperture priority mode, if you lower the F-number, the image gets brighter.
• Problem 1c. True or False? In-lens leaf shutters expose the center of the field of view longer than the corners.

• Problem 2. Which of the following statements are true about pinhole photographs? Assume the surface on which the image is formed is flat. Circle all that apply.
  • (a) They are linear perspectives.
  • (b) They have infinite depth of field.
  • (c) Straight lines in the world can become curved in the photograph.
  • (d) They are upside down, but if you rotate them 180 degrees they look correct.
  • (e) They are upside down and if you rotate them they still read read backwards.
  • (g) They are dim, unless the scene is very bright or you use a very long exposure.
  • (h) They are in black and white.

• Problem 3. What is the minimum number of vanishing points there can be in a linear perspective drawing of a cube? Assume the cube is an open wire frame (or it's made of glass, so you can see all 12 edges regardless of your viewpoint). Assume also that the cube measures 1 foot on a side, and you can't stand more than a few feet away from it. Circle the best answer.
  • (a) Zero
  • (b) One
  • (c) Two
  • (d) Three
  • (e) Infinitely many
  There will be one vanishing point in a linear perspective image for every direction of light that is not parallel to the picture plane. No matter how you orient a cube, there will be at least one such direction, which goes "away from you". This direction will have a vanishing point.

• Problem 4. You're taking a picture of an athlete at f/2.8, 1/200s, and ISO 200. You realize that you want twice as much depth of field and half as much motion blur. What new settings do you use, if you want to keep the same amount of exposure?
  • (a) f/4, 1/400s, ISO 200
  • (b) f/4, 1/400s, ISO 400
  • (c) f/4, 1/400s, ISO 800
  • (d) f/5.6, 1/400s, ISO 800
  • (e) f/5.6, 1/400s, ISO 1600
  In order to double our depth of field we must use f/5.6, and in order to cut motion blur in half we must use 1/400s. The former decreases light by 4x and the latter decreases light by 2x, so we should increase our ISO by 8x to compensate, giving us answer (e).

Due Date

Assignments are generally due on Sunday at midnight at the end of the week in which they're assigned. This leaves you free to start thinking about the next assignment during your next section. Sometimes lateness is unavoidable, so familiarize yourself with the lateness policy in the course outline.

FAQ

Q: My Camera doesn't have manual focus. How can I force everything to be out of focus?

A: Even if your camera doesn't provide manual focus, you can usually force the focus to be anything you want. Just point at an object that's not in your scene but at the desired depth, press the shutter button halfway to autofocus on it, then with the button still half-pressed, swing around to aim at your scene and press the button fully. Does the exposure come out wrong when you do this? We'll talk in class about focus-lock and exposure-lock functions, which not all cameras have.

Q: At what resolution should I upload my photos?

A: Google resizes your photos for viewing, and gives you 1GB of free storage. This should be enough that you can safely upload full resolution images for the course. If you're worried about running out of space, you could also resize your images in Photoshop, Picasa, or a similar program before upload to something smaller.

Q: Are we allowed to edit our photos in Photoshop before uploading? How much editing is acceptable? Do we have to say what we did?

A: In general, most requirements won't necessitate any image manipulation in Photoshop, and for this first assignment, none of them do. However, some requirements for future assignments will specifically involve image editing, and even for those that don't, you're always welcome to process your images in Photoshop or any other program. Just keep in mind that if you do edit your photos in Photoshop, you should definitely state what you did in the Picasa comments. For example, you might say: "I used Photoshop to increase the saturation and darken the sky". Finally, keep in mind that Photoshop should not be used as a substitute for proper use of your camera or for faking a requirement. For example, for this assignment your underexposed or overexposed photo must be that way from the camera -- you're not supposed to just take a normal photo and use Photoshop to make it way darker or brighter.