Features
Although the EOS-1D Mark IV is quoted as having an APS-H-sized sensor like its predecessor, it is interesting that the dimensions of the imaging device have actually shrunk marginally from 28.1×18.7mm in the EOS-1D Mark III to 27.9×18.6mm in the new camera. As before, this puts it between an APS-C and a full-frame device, and it produces a 1.3x focal length magnification factor. However, this isn’t the only difference between the two sensors. For many people, the most important point is that the effective pixel count has been increased from 10.1 million to 16.1 million, and this has necessitated a drop in pixel size (in microns) from 7.2×7.2µm to 5.7×5.7µm.
This could have negative repercussions for the signal-to-noise ratio, but Canon has introduced a range of measures to help minimise image noise levels. For instance, the photodiodes occupy a greater proportion of the pixel area to increase the size of the light-receiving area and a new material has been used for the primary colour filter to boost light transmission. As with the EOS 7D and EOS 550D, the microlenses over the EOS-1D Mark IV’s sensor are gapless and closer to the photodiode than before to boost light capture. Canon also claims that noise suppression has been improved and that doubling the internal gain of the preamp helps increase the signal-to-noise ratio.
All these measures, plus improvements brought by the switch from dual Digic III to dual Digic 4 processors, means Canon has felt confident enough to give the EOS-1D Mark IV a sensitivity range of ISO 100-12,800, which can be expanded to the equivalent of ISO 50-102,400. The impressively high maximum sensitivity setting matches the highest value possible with the camera’s main competitor, the Nikon D3S.
The EOS-1D Mark IV is primarily aimed at photojournalists and sports photographers who demand a high continuous shooting rate. Despite its much higher pixel count, the EOS-1D Mark IV is capable of shooting at the same maximum rate – 10fps – as its predecessor. This gives the Canon camera a 1fps advantage over the Nikon D3S.
Given the problems with the EOS-1D Mark III’s AF, it is hardly surprising that Canon has introduced a completely new system for the EOS-1D Mark IV, with new hardware and firmware. I will cover this in greater detail later, but the important aspects are that it has 45 user-selectable points, with 39 being f/2.8-sensitive cross-type.
Video-recording technology is fast becoming essential in a photojournalist’s camera and the EOS-1D Mark IV can record movies as MOV files at three sizes. These are 1920×1080 pixels (Full HD), 1280×720 pixels (HD) and 640×480 pixels (SD) with MPEG-4 AVC compression and a selection of frame rates available at each size.
With such a well-specified camera it seems almost churlish to point out that the EOS-1D Mark IV doesn’t have a built-in level like Canon’s top-end APS-C-format DSLR, the EOS 7D, or the Nikon D3S. And now that Canon has finally seen the light and introduced wireless flash control via the pop-up flash unit of the enthusiast-level EOS 7D, perhaps it is time for the company to include the technology found in its ST-E2 Speedlite Transmitter in a professional-level DSLR.
