Figure 6-87: A moving subject in extremely low light as captured in Program Mode (Left) and AMB mode (right). AMB takes 4 shots at any given ISO in rapid succession, and merges areas that don’t move (reducing noise in those areas), but not including areas of images that contain blur. If you look very closely, you can see higher ISO noise around the pendulum, but not around the areas that didn’t move. This is an impressive algorithm. |
AMB is designed to make things look less blurry in borderline situations. It works almost identically to Multi-Frame Noise Reduction (MFNR, Section 6.21.2), in that it, too, takes four sequential images and attempts to merge them in-camera. But AMB applies a little more intelligence to the merging, analyzing each individual shot, looking for the sharpest parts of each. If an object is sharp in one of the frames but blurry in others, only the sharp part will be included in the merged image. This results in a sharp picture with relatively low noise in most of the shot. (Figure 6-87.)
The only real differences between MFNR and AMB are 1) you can use the MFNR feature at ANY ISO, resulting in even less noise at any given setting, and 2) you have full control over the camera’s features, such as exposure compensation, ISO, White Balance, spot metering, etc.
Figure 6-88, which was taken in extremely low light (although it doesn’t look it), provides a little more insight as to what is going on inside the camera when it handles subjects that move. Both of the sky buckets were moving during the 4 shots, and if all 4 shots had been averaged together you would have seen one big blur. The camera, while processing the shots, noticed the movement, and said “I can’t merge these – it’ll be a blur!”. And so it picked one frame where they were sharp, and just didn’t merge that part of the image from the other frames. You can see evidence of this if you look really closely at the parts that are moving – the noise level in and immediately around the skybuckets is more intense than the other, non-moving areas immediately around them.
TIP: If you’re shooting either RAW or RAW+Jpg, and switch to either Anti-Motion Blur or Handheld Twilight, the camera automatically switches you to .jpg only, of quality “Fine”. |
|
Figure 6-88: Things that move during the AMB exposures will be noisier than the things that don’t move. If you look carefully, the noise in the sky immediately surrounding both of these sky buckets is higher than the rest of the sky. A minor artifact to a very impressive feature. |
