mirrorless cameras offering high-resolution APS-C sensors and consecutive shooting speeds of up to 10 frames-per-second, what's left to make a $6,000 full-frame DSLR a compelling purchase, especially for amateur photographers? Low-light performance, for one -- the Canon EOS-1D X and Nikon D4 are both capable of capturing images at up to ISO 204,800, letting you snap sharp photos in even the dimmest of lighting conditions. The benefits of a top sensitivity of ISO 204,800 are significant -- jumping from one ISO to the next doubles your shutter speed. So an exposure of f/2.8 at 1/2 second at ISO 400 becomes 1/4th at ISO 800, 1/15th at ISO 3200, 1/60th at ISO 12,800, 1/250th at ISO 51,200 and a whopping 1/1000th at ISO 204,800 -- fast enough to freeze a speeding car.
Both Canon and Nikon have yet to allow us to take away samples shot with the 1D X or D4 -- the companies even taped CF card slots shut to prevent show attendees from slipping their own card in -- but we were still able to get a fairly good idea of high-ISO performance from reviewing images on the built-in LCDs. At the cameras' top sensitivity of ISO 204,800, noise was visible even during a full image preview. Zooming into the image revealed significant noise, as expected. However, within each camera's native range of ISO 100 to 25,600, noise was barely an issue at all. Both cameras are still pre-production samples at this point, so we'll need to wait for production models to make their way out before we can capture our own samples, but based on what we saw when reviewing ISO 204,800 images on the built-in LCDs, that incredible top-ISO setting may actually be usable. Scroll on through the gallery below to preview some top sensitivity shots on the Canon EOS-1D X (camera poster) and the Nikon D4 (Japanese model), and join us past the break for an even closer look in our video hands-on.