By : Nikon School Blog | 29 Sep, 2016 |
Some of the greatest images have been shot in low light. Their greatness is partly due to the fact that getting everything right in low light is a huge challenge. As the shutter speeds plummet when you're shooting in low light, it gets more and more difficult to hold your camera steady.
Thankfully, the Nikon technicians understood this challenge way back in 1994, and they used the world's first optical image stabilisation in the Nikon Zoom 700 VR film compact camera. They called this technology Vibration Reduction or VR. This term has stuck since then and been followed in numerous world famous NIKKOR lenses.
Generally, 1/125 to 1/60 has been observed to be stable shutter speeds. However, when it gets darker, it is necessary to open the shutter longer to let more light in. Slower the shutter speed, more the chances of a blurred image. At speeds of 1/30 and slower, even experienced photographers can experience camera shake. The VR technology stabilises the lens in such cases, so that the photographer gets a stable image even at speeds of 1/30 or less.
Nikon VR technology is used in most modern NIKKOR lenses. When there is no camera shake at fast shutter speeds, light from the subject reaches the focal plane at the desired spot through the lens. But due to camera shake at slow shutter speeds, this light falls on a different point of the focal plane, causing the visual blur. Nikon's optical VR system used in NIKKOR lenses adjust the lens to ensure the light falls on the desired spot on the focal plane so that the image is free from camera shake.
To do this, a complex mechanism involving a VR lens element, sensors, microcomputers and driving motors are used. You can read in detail about this mechanism in this excellent article - http://www.nikon.com/about/technology/rd/core/software/vr_e/
So when does Nikon's fascinating VR technology help us? Not just in low light situations and with slow shutter speeds. While using telephoto lenses, you may experience camera shake even at shutter speeds of 1/125 or 1/250 . This happens due to the so called 'thumb rule' that the minimum shutter speed to be used with a lens is the reciprocal of the focal length. So, with a 500mm lens, you will need at least 1/500 sec shutter speed to ensure a steady shot, and 1/800 s with an 800 mm lens. VR is a great help here. As the ambient light may not permit you to use very fast shutter speeds, a VR lens offering 2 to 3 stops stability will allow you to get results of a 1/500 second speed even at 1/125 (2 stops) or 1/60 (3 stops).
The latest VR technology can compensate for upto four stops. This means, you can safely use a 500mm lens at 4 stops below the required 1/500 s speed, ie, 1/30 ! Incredible isn't it ? Of course, you can also increase ISO to be able to use faster shutter speed, without using VR. However, increasing ISO always comes at the cost of image quality. So VR allows you to stick to lower ISOs, and preserve image quality.
Unknown to many, VR not only gives you a steady shot, it also allows you to view an image properly while looking through the viewfinder. The VR system is activated when you half-press the shutter release button and the lens is adjusted continuously so that the image visible in the viewfinder is stable.
Nkon's intelligent VR system is also capable of differentiating between deliberate camera movements related to composition and actual camera shake. This is achieved through a system called "Centering Before Exposure" which only Nikon VR technology has.
Nikon VR is available as Normal and Active Modes in some telephoto lenses. In Normal mode, slow and large camera movements are assumed to be deliberate movements and not compensated. In active mode, these movements are compensated for, resulting in smoother viewing and shooting in conditions like, from a moving vehicle. A recent addition is the 'Sports mode' in the latest NIKKOR telephotos which is more effective while shooting fast action like sports or wildlife.
Even while mounted on a tripod, factors like wind, or mirror movement can cause slight camera shakes during long exposures. Some NIKKOR lenses have an advanced VR system which recognises this type of shake and adjusts the VR accordingly.
It took the expertise of lots of brilliant minds to perfect the Nikon VR technology. With time, photographers the world over can rest assured that Nikon will go on improving its VR technology to even higher standards to ensure blur free images in the most challenging conditions.