Resolution, noise and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using matching 105mm macro lenses. We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution is at the specified sensitivity setting.
When Nikon announced the launch of the D3S, it raised the bar for noise control and sensitivity. Canon has matched the D3S’s maximum sensitivity setting of ISO 102,400 for stills and video capture with the EOS-1D Mark IV, but the results are extremely noisy.
When the noise reduction is turned off the level of noise is off the scale of our testing regime, so we are unable to report meaningful figures at ISO 51,200 and 102,400. Even in the raw files, detail resolution is heavily compromised at these highest expansion settings and I would avoid using the ISO 102,400 option.
Noise is well controlled up to around ISO 1600. Between this point and ISO 51,200 (inclusive), JPEG files taken with the noise reduction set to its default standard level have more chroma and luminance noise than comparable JPEGs from the full-frame, 12-million-pixel Nikon D3S.
Although the level of noise in JPEGs captured by the Canon camera at ISO 102,400 with the noise reduction set to its default level is lower than that in JPEGs from the D3S, the EOS-1D Mark IV’s files contain much less detail.
Green and red splodges are visible in the Canon camera’s images, especially in the shadows, even when they are sized to make small prints.
At more routine sensitivity settings, the EOS-1D Mark IV is capable of recording a high level of detail.
UNDERSTANDING THE GRAPH This graph shows the brightness values recorded by the test camera when it is used to photograph a stepped graduation wedge. The wedge has transmission values in 1⁄2EV steps ranging from 0 to 12EV. The camera’s exposure is set so the 12EV section in the wedge has a brightness value of 255. Software analysis of the image then determines the recorded brightness values of all the other steps and calculates the camera’s dynamic range.
