Roger Clark
Banned
I'm attaching a some plots of an accelerometer attached to a camera to illustrate the vibrations due to framing during imaging. In the attached plot, I did two tests. My accelerometer measures acceleration in units of g (acceleration due to gravity = 1) from which velocity and position as a function of time can be derived. My accelerometer samples at 320 Hz. These data have been high pass filtered, meaning they show higher frequency vibrations only, and not movement due to panning.
First I tightly held the Canon 1D Mark IV with 500 mm f/4 L IS attached tightly in my arms and held tightly to my chest. With one hand on the camera and pushing the camera tightly to my chest and a finger on the shutter button, I fired two short sequences at 10 frames per second. This test illustrates my ability to dampen high frequency vibrations caused by mirror movement and is shown as the red curve in the figure. Mirror slap causes vibration up to about 25 microns (about 5 pixels) in 1/320 second.
The second test was a bird in flight test. I ran 8 tests and this sequence is the best (lowest vibrations). In this test, I held the 500 with one hand with my elbow tucked to my side. With my second hand, I held the camera tightly to my cheek and firmly in my hand with my index finger on the shutter button. I panned and during panning, I fired two sequences at 10 frames per second (blue line in the plot). The fact that the two sequences have timing where firing frames occurs at nearly the same time is a coincidence.
The BIF results show vibrations of up to almost 80 microns (the 1D mark IV has 5.7 micron pixels) in 1/320 second, or over 13 pixels. The peaks are caused by mirror slap and there is usually a bounce of the mirror also recorded in a second peak. Then the camera settles down a little when the shutter opens, but during the actual imaging period, vibrations of over 30 microns occur in 1/320 second (over 5 pixels).
The vibrations recorded are limited by the accelerometer and the vibrations at 1/1,000 second (kilohertz) are likely higher. But even assuming these numbers are the maximum, and that the vibrations scale linearly, a 5+ pixel shift in 1/320 second translates to about 1.7 pixel shifts at 1/1,000 second exposures, and 0.8 pixel shift at 1/2,000 second exposures.
Image stabilization does a great job of producing sharp images. This data says that the IS is removing the effects of these vibrations at least for exposure times as fast as 1/2,000 second and that one should use IS up to at least 1/2,000 second.
A side note. I found an interesting effect on hand holding. When hand holding and pointing in one direction at a static subject, I produced more vibrations, but when I started panning, those body-induced vibrations smoothed out. So I would say hand held panning works better than static hand held imaging.
Roger
First I tightly held the Canon 1D Mark IV with 500 mm f/4 L IS attached tightly in my arms and held tightly to my chest. With one hand on the camera and pushing the camera tightly to my chest and a finger on the shutter button, I fired two short sequences at 10 frames per second. This test illustrates my ability to dampen high frequency vibrations caused by mirror movement and is shown as the red curve in the figure. Mirror slap causes vibration up to about 25 microns (about 5 pixels) in 1/320 second.
The second test was a bird in flight test. I ran 8 tests and this sequence is the best (lowest vibrations). In this test, I held the 500 with one hand with my elbow tucked to my side. With my second hand, I held the camera tightly to my cheek and firmly in my hand with my index finger on the shutter button. I panned and during panning, I fired two sequences at 10 frames per second (blue line in the plot). The fact that the two sequences have timing where firing frames occurs at nearly the same time is a coincidence.
The BIF results show vibrations of up to almost 80 microns (the 1D mark IV has 5.7 micron pixels) in 1/320 second, or over 13 pixels. The peaks are caused by mirror slap and there is usually a bounce of the mirror also recorded in a second peak. Then the camera settles down a little when the shutter opens, but during the actual imaging period, vibrations of over 30 microns occur in 1/320 second (over 5 pixels).
The vibrations recorded are limited by the accelerometer and the vibrations at 1/1,000 second (kilohertz) are likely higher. But even assuming these numbers are the maximum, and that the vibrations scale linearly, a 5+ pixel shift in 1/320 second translates to about 1.7 pixel shifts at 1/1,000 second exposures, and 0.8 pixel shift at 1/2,000 second exposures.
Image stabilization does a great job of producing sharp images. This data says that the IS is removing the effects of these vibrations at least for exposure times as fast as 1/2,000 second and that one should use IS up to at least 1/2,000 second.
A side note. I found an interesting effect on hand holding. When hand holding and pointing in one direction at a static subject, I produced more vibrations, but when I started panning, those body-induced vibrations smoothed out. So I would say hand held panning works better than static hand held imaging.
Roger