Do you know that SLR (single-lens reflex) cameras have a problem that the built-in mirrors and shutter in the main unit cause camera shake and degrade the image quality?
Though camera manufacturers and some enthusiasts have been aware of the problem, they had no idea how serious (or minor) the problem really is until recently.
However, Tani Electronics Corp and the Nishi Lab of the University of Electro-communications (UEC) introduced a measurement tool that will change the circumstances. They developed a method to easily and accurately measure the effect of camera shake correction.
The results of measurements using the new tool are as follows. The resolution of an SLR camera was substantially reduced to 1/4 or lower by the mirror shock (vibration generated when the mirror bounces up).
Next, it was confirmed that the vibration generated by releasing the shutter remains even when a picture is taken after a certain period of time from the mirror lockup to prevent a mirror shock.
Then, the Nishi Lab and Tani Electronics found that camera shake significantly worsens when a lighter tripod (approx 1.5kg) is used. Also, they conducted a quantitative investigation about the influence of the installation direction of the tripod.
"There is no point in enhancing resolution unless we take some measures to reduce the vibration of a camera unit as a whole including a tripod," said Kazuki Nishi of UEC.
When a tripod is used, the above measurements were carried out after disabling the image stabilizer, as directed in instruction manuals of cameras and lenses. And, to make sure, the researchers conducted the measurements using several cameras with the image stabilizer function turned on and confirmed that camera shake worsens.
The Nishi Lab and Tani Electronics improved the LED display used to measure the effect of camera shake correction and enabled to measure vibration caused by the mirrors and the shutter. As a result, they succeeded in detecting and quantifying the trajectory of camera shake with an enhanced temporal resolution. With the new measuring tool, various kinds of vibration can be measured and quantitatively evaluated directly from pictures taken by a camera.
"We hope that this measurement tool will be used to totally evaluate various kinds of vibration such as caused by a tripod, not just camera shake," Nishi said.