Autofocus
Like compact and Micro Four Thirds cameras, the Samsung NX10 relies on contrast-detection AF to focus its lenses. It does this by shifting focus back and forth until it detects the point of most contrast.
For example, imagine a black box and a white box placed side by side. If the image is out of focus, a grey blur will be seen where the two boxes meet, with little contrast between them. As the lens focuses, the boxes will become sharper, creating more contrast between the two boxes. The camera will then go slightly beyond this point and will detect when the contrast begins to decrease. It then snaps back to the point of peak contrast, and the image will then be in focus.
The contrast-detection AF in the NX10 works very well, and given a static object the lens locks on quickly. It struggles a little in low light, but thankfully there is a green AF assist beam that provides enough light for focus to be achieved.
Although continuous focus is available, most photographers would be better off leaving the NX10 in single AF mode. While the NX10 is clearly not designed to photograph fast-moving objects, the continuous focus can cope with people walking or moving at a moderate speed.
Manual focusing is very good. Like the Panasonic and Olympus Micro Four Thirds cameras, switching to manual focus and turning the camera’s focus ring magnifies the image in the viewfinder or on the rear screen. This makes it possible to focus with a high degree of precision, and I found that it is actually easier to focus manually using the EVF of the Samsung NX10 than it is using the optical viewfinders of many DSLRs.
Image: Although the contrast-detection AF is not designed for taking images of moving subjects, with careful pre-focusing and timing it is possible to capture moderately fast movement.
