ISO51200 achieved by removing the cause of noise
When shooting indoors, ISO6400 is typically all that is required, but as the X-T1 is designed for professional use it is better to expand the range so, for example, it’s easy to shoot concerts or sporting action indoors with a telephoto lens.
But higher sensitivity also means a drop in image quality, so we challenged ourselves to produce a maximum sensitivity of 51200 – a first for FUJIFILM – that delivers the same level of image quality as ISO25600. FUJIFILM’s requirements for image quality are normally severe, but this goal was achieved thanks to the effectiveness of the circuit design, noise reduction and various algorithms.
Normally, signal processing reduces noise after the digitizing the signal from the sensor, but we wanted to reduce noise before digitizing. When noise appears on the image sensor it does so in horizontal lines that are especially noticeable in low contrast images.
This is made worse by wires which, when arranged close together, cause an electromagnetic problem. To overcome these issues, the sensor’s components and circuit board were carefully designed through numerous simulation tests. It wasn’t easy to achieve noise reduction given the size of the components and the limited space available.
Temperature is also important. When the sensor gets hotter, noise increases so we focused on heat dissipation design to ensure the sensor wouldn’t get too hot.
Additionally, the amount of black in an image affects quality at high sensitivities. On the computer, we examined how color reproduction and gradation change according to the exposure time and temperature then optimized the system to keep blacks consistent.
We hope this outstanding performance at sensitivities up to ISO51200 will expand the shooting options for users when photographing moving subjects, subjects at a distance or when taking photos at fast shutter speeds without using flash or a tripod. We hope that users will challenge the camera’s capabilities and capture images that could not be taken before.