Avoiding Blur on slow shutter speed shots

Blur, or camera shake, occurs when there is some movement of the camera (or the subject) when the image is being captured. In this post, we will ignore the subject movement and concentrate on avoiding blur in the camera. I have only tested this on my Canon camera/lenses, so I am not 100% sure if it is an issue with other makes.

Back in December, I was taking images of our newly decorated Christmas tree with all its lights and ornaments. I wanted to get a well exposed image that showed a little detail outside the window, had the lights at a reasonable brightness and showed reflections of the lights in the windows behind the tree. So I waited until dusk, place my camera on a solid tripod and worked out that the best exposure – which turned out to be 3 seconds at f14, so that I could get the depth of field necessary to get the reflections in the wooden floor sharp.

I took the first shots using a wireless remote plugged into my Canon 5D Mk2, fitted with the 24-105mm lens, zoomed in on the LCD screen and was surprised to see double images of the lights:

Camera Blur

I went through a series of steps – is the tripod head properly tightened, am I walking on the wooden floor during the exposure and causing some movement in the tripod that way. Ah… perhaps it is the mirror that is causing a vibration as it moves out of the way. So, I went to the custom functions on my Canon menu and set the mirror lock function, where the first press of the remote control moves the mirror, and then you can wait a second or two before triggering the shutter.

Still no luck – the next set of exposures had exactly the same problem. I tried everything – moving out of the room before pressing the remote shutter release, trying shorter shutter speeds by increasing the ISO, but virtually all images had the same problem.

Strange as it may seem, I tried for an hour to get to the bottom of this problem. Then, a flash hit me (not literally as this is natural light….) I remembered reading that the Lens Stabilization mechanism on Canon lenses could cause a blur when mounted on a tripod. If you recall, lens stabilization works by having the center glass elements of a lens in some sort of moveable frame and there is a feedback mechanism to move this framework if it is detected that the camera/lens has moved during the exposure. Of course, my camera/lens was on a tripod and so there should have been no movement, so this should not have kicked in. However, it seems that for exposures over a second or so, the lens stabilization does do a check of stability, even though there is no movement, and this slight movement of the lens elements causes blur.

Once I realized this, I flipped the switch on the lens to turn off stabilization, and the next image was pin sharp:

Sharp lights

The final photo is also attached (of course, it had gone dark by now and so the view outside had disappeared), but I think the reflections of the lights in the windows makes for a good effect. So, the moral of the story is – with Canon stabilized lenses, always turn off stabilization when you have the camera on a tripod!

Final image