The second and third weeks of our course, Making Science and Engineering Pictures (MITx0.111), are the most challenging. It’s here where the students dig into the inner workings of their cameras and grapple with the relationships between aperture, exposure, lighting, and depth of field.
Video tutorials for weeks 2 and 3 show and tell the basics while interactive tools give learners the opportunity to twiddle and work through what-if scenarios.
With the basic concepts in hand, the next step is to try it yourself. In the week 2 assignment you put your camera on a tripod and photograph your chosen object or device at a series of f stops while keeping all other parameters constant. This means setting your camera in aperture-priority mode and “stopping down” your lens from (for example) f/4, to f/8/, to f/11, to f/22 – and even down to f/32 if your camera includes that option. By fixing the camera in place (with the tripod), and keeping all other variables constant, you can easily see the differences in your images. At the larger apertures (smaller f-stop numbers) the nearer elements of your object appear in sharp focus while those at a distance from the camera remain fuzzy. But as you tighten the camera’s aperture (larger f-stop number), more and more of your image comes into focus. As photographers put it, you have a greater depth of field. As a topper to the assignment, we asked the students to remove their camera from the tripod and take one last picture, at their smallest aperture, with the camera in hand.
Students submitted their week 2 image collections on VoiceThread and then narrated their production. It was wonderful watching and listening to them as the penny dropped. “Now I get the relationship between the aperture and the exposure.” “I like this picture, taken at f/22, because I can see all the details of the circuit board at the front and at the back.” “Wow, I can’t believe how out of focus that is – I guess I really do need to use a tripod.”
Wonderfully creative, many of our students played with the assignment and experimented beyond the boundaries. One student set up his VoiceThread as a mystery by setting his object in front of a backdrop and challenging his peers to figure out the backdrop as it slowly came into focus over the course of the image series. Others submitted multiple aperture-priority series with different lighting options. Still others decided to expand their chosen objects to challenge themselves further and figure out the best way to capture odd shapes or dimensional irregularities.
The week 3 assignment asked students to photograph their object or device with a number of different lighting scenarios. Daylight, augmented with a secondary light source, and to experiment with unusual source of light. As with the week 2 assignment, we asked students to hold the other imaging variables steady in order to fully grasp the impact of altering light.
Students experimented with flashlights, LED key chains, desk lamps, candles, light boxes, headlamps, and – my personal favorite – the light radiating from a computer screen. For the students who’ve stayed with the same object or device they selected in week 1, it’s a pleasure to see how different the same object can look, depending on how the image is taken. Photographing the same device also allows us to witness the students development over time as we see the quality of their images improve.
I am quite taken with the playful and experimental nature of their approaches. A Drosophila geneticist marvels over the different appearance of her fruit flies in a blue light. A materials scientist figures out a way to change the background color by projecting colored light onto a white paper background. Many students attempt bouncing light with foam core or white poster board. One students marvels over the subtle changes in daylight over the span of the hour she spent shooting her images near a sun-filled window.
Our edX platform statistics tell us how many students view each of our course videos everyday, but it’s far more revealing to hear the language of the video tutorials pop up in the students’ narration of their own work (diffuse, bounce, negative spaces, horizon…) and to notice Felice’s suggested strategies appear in their work (a curved paper background, pairing objects, attention paid to the camera’s angle). Evidence of their learning appearing like footprints on a beach.
Assessment in this course happens all along the way. It’s a continual part of the learning. And our students are acquiring knowledge in multiple venues – from the course’s video tutorials, from the sample assignments, from the work of their peers, from the comments of their peers, and – most importantly – from their own experiments.
We Teaching Assistants (TAs) divide up the VT groups between us and attempt to provide timely feedback, while the images they’ve taken are fresh in their minds. Most students get VT comments from at least one TA and two or three peers. The quality of the comments vary, but the ones I’m the most grateful to hear are those that ask an informed question, make an intriguing observation, or refer the student to another VoiceThread that might shed some light on a problematic issue.
I can tell that our students are transferring their knowledge from one week to the next, building on what they’ve learned and applying what they see in the work of others. They are engaged in complex work, they have flexibility with regard to when and how they do the work, they engage with each other, and there is a real sense of mastery coming through.