Tag Archives: science

The Science of Drag Shutter

Student intern at Umass Memorial cancer research lab

EXPOSURE INFO: Canon 40D, 16-35 f/2.0L, 1/2 sec @ f/9.0, ISO 100, two Pocket Wizard triggered Quantum Q flashes at 1/4 power, cross-lighting subjects from the sides

This was a fun assignment to shoot a magazine cover of an independent high school student who did an internship at a cancer research lab. It was also a great exercise in building up to a final shot by adapting to the conditions on site.

There were a number of things I wanted to convey in this shot. First of all, even though he was still in high school, this was serious and meaningful work the student intern was doing. Hence the “game faces” they are all wearing.

I also wanted to give some indication that the lab was pretty large – this was complicated by the fact that the space was divided up into narrow sections by the counters and shelves you see on either side of the subjects. I opted for elevating the camera position, by way of a short step ladder, to allow the viewer to see the rows of each lab section converging into the distance above the subject’s heads.

Lighting was tough. Since it was to be the cover shot, I really wanted to shoot as low an ISO as I could to avoid noise. I also wanted enough DOF to get the three subjects in focus. At f/9.0 and ISO 100 with a typical sync speed of 1/125th, the background would have gone way too dark so I let the shutter drag all the way down to 1/2 sec to bring the background values back up.

After taking a few frames to tweak the lighting ratio between the strobes and the existing light, I took a series of shots with the camera locked down tight… these just didn’t provide the drama I was looking for so I started taking more shots while slightly jiggling the camera during the exposure which knocked the background a bit out of focus. The strobes kept the subjects nice and sharp. Since you never can tell all of the consequences of doing drag shutter shots just by chimping them on the camera’s LCD, it’s necessary to capture a lot of images to ensure you get some that are good enough.

The shot I chose here is slightly cropped at the top (I left extra space for the magazine title), I punched up the vibrance and added an edge darkening vignette in Lightroom.