High Dynamic Range Test Chart
The High Dynamic Range (HDR) test chart has a density range exceeding 120dB (optical density >6.0). This chart allows you to measure the tonal response, noise, and dynamic range of HDR cameras with a single image instead of multiple, exposure bracketed images. The ITHDR36 contains slanted edges with 4:1 contrast for measuring MTF. The edges have an MTF50 >= 16 cycles/mm, which is about 3 times better than the best inkjet charts. The middle gray background density closely resembles our 36-patch Dynamic Range target, enabling proper exposure with automatic exposure cameras. HDR test targets with black backgrounds tend to overexpose the brighter patches with auto-exposure cameras.
The HDR chart’s active area of 197 x 235mm is a good fit for both the DNP Standard Color Viewer and ITI LED lightbox. Imatest recommends using the HDR Target with a high illuminance light source (close to 10,000 Lux) in order to provide sufficient light to test image sensors over their range of sensitivity. The chart is well suited for measuring both camera and sensor dynamic range, which are fundamentally different. Camera DR measurements are affected by flare (stray) light in the lens. They represent real-world performance. Sensor measurements are based on the patch pixel and noise levels in unprocessed RAW images, using the technique described in Multicharts/Multitest/eSFR ISO Noise, which fits data to an equation based on dark and photon noise.
The Imatest 36-patch High Dynamic Range Target includes an acrylic frame which can be excluded.