CS178 Assignment 2 - Sports and Action
Always pacing, this lion at the San Francisco Zoo provided plenty of practice when learning to blur the background in a panning action shot.
Photo by Michael Broxton
One of the first problems you will encounter as a photographer is that the world doesn't stand still and wait for you to take a photo. Many interesting compositions are fleeting, so the photographer has to be somewhat opportunistic. Sometimes you will take a hundred photos and only get a handful of good ones.
This week we'll be capturing moving things. There are tons of interesting moving things around campus: cyclists, people playing ultimate frisbee, cars driving past, squirrels dashing from tree to tree. Animals in general are delightfully uncooperative, so if you have a dog or cat, this might be a good week to take a photo of them running or jumping or chasing a toy.
The key difficulty in capturing moving objects is getting enough light. The shutter speed needs to be short enough to prevent motion blur. You usually compensate for this by using a large aperture and increasing ISO. However, you quickly encounter trade-offs. For example, increasing the aperture shortens the depth of field and makes precise focus more important (and challenging). Autofocus takes time and a slow autofocus system may not be able to keep up with the action you are trying to capture with your fast shutter speed, resulting in a missed shot. If you're able to set up the shot, one good trick is to prefocus at the depth you're expecting, so that the photograph can be captured at the instant the object moves through the point of focus. As you can see, capturing a unique photograph often involves manipulating several of the camera's control systems at once!
This assignment is similar in format to the first one. There are four requirements this week, which you will meet by taking photographs, uploading them as a new album to the Picasa account you made last week, and adding comments below them. You must meet each requirement in at least one photo, and every photo should meet at least one requirement. Upload from 5 to 10 photographs in total.
As usual, we've post an example 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) from 2009 and 2010. 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!
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.
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 technical problems
Starting this week, we'll be including some technical questions in each assignment to help you make sure you're keeping up with the material. You don't have to turn in your answers; they're just for your educational benefit, plus they are an excellent way to prepare for the midterm and final exams. After the assignment's due we'll post the answers here, and we'll also discuss some of them in Section, time permitting. In this case, the first two should be pretty easy and the last two are more in line with the sort of questions we might ask on the midterm.
Note: answers have now been marked in bold.
Due Date11:59PM, Sunday, April 10, 2011
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. Here's the lateness policy from the course outline:
© 2009-2011 Marc Levoy, Andrew Adams, and Jesse Levinson