Cosmojetz

Nikon D7000, 80mm (35-80), 1/125, f/5.6, ISO 800

This semester I’m going to blog a few of the exercises we do in my photography class. I want students who miss class to be able to see what we did. And for those of you who aren’t in the class, these are good examples of some photography basics (even if they aren’t the most spectacularly fascinating photos ever taken).

The topic for this lesson is shutter speed. Our model is a small wind-up device called Cosmojetz, the creation of artist Chico Bicalho.

I took the shot above holding the camera in my hands and using a middle-of-the-road shutter speed.

Nikon D7000, 80mm (35-80), 1/4, f/32, ISO 800

Next I slowed the shutter down a bit to demonstrate camera shake. This is the shot you almost never want, with everything a big blurry mess. As a photographer, you need to figure out how steady your hands are. I can’t shoot anything much below 1/30 (depending on the circumstances) before the blur starts to ruin my pictures. However, if you don’t have four decades of caffeine behind you, your hands may be more stable than mine.

Note that the one thing that doesn’t move in this shot is the dust on the lens, because when the camera shakes the dust moves right along with it, staying stationary in relation to the image recording chip. You won’t see the dust in any of the rest of the shots because when I noticed it I remembered to do my job as a photographer and wipe the lens with a lens cloth.


Next we locked the camera down on a tripod to completely eliminate camera shake. And we set the subject in motion. Here’s a video of what Cosmojetz looks like when it bounces around:

We started with another middle-of-the-road shutter speed:

Nikon D7000, 42mm (35-80), 1/125, f/4.5, ISO 800

As anyone who has ever tried to take a picture of a three year old can attest, rapidly moving objects can be tricky to photograph. Though 1/125th of a second seems like no time at all to us, a moving object can travel quite a bit even in such a small fraction of an instant. Thus the blurring that clearly indicates the subject is on the go.

Nikon D7000, 42mm (35-80), 1/250, f/4.2, ISO 800

Increasing the shutter speed still further reduces the blur to manageable levels, though you can still see a bit here and there. In shutter priority mode, the camera has been automatically adjusting the aperture for us to make sure we get a good exposure. But now we’ve reached the limits of the lens; the aperture won’t open any wider, and we’re starting to sacrifice image quality.

Of course at this point we can fix the slight under-exposure in Photoshop, like this:

Nikon D7000, 42mm (35-80), 1/250, f/4.2, ISO 800, adjusted

But if we want to freeze the motion entirely, we’ll need to speed the shutter up still farther. And that will mean increasing the ISO (making the camera’s image sensing chip more sensitive to light) to get a good exposure.

In the shot below, motion blur has been completely eliminated. The only way you can tell that the subject is moving is that otherwise it would have to be hovering in mid-air.

Nikon D7000, 42mm (35-80), 1/1600, f/4.2, ISO 6400

The lesson ends at the opposite end of the scale. Slowing back down to a quarter second (the speed that gave me such terrible camera shake earlier), transforms the rapidly-moving subject into a ghost, barely visible in the upper part of the photo.

Nikon D7000, 42mm (35-80), 1/4, f/25, ISO 800