SENSOR-TIVITY

It's interesting to see how the trajectories of both Canon and Nikon have changed when it comes to image noise. Where Nikon has purposely stalled its full-frame D700 and D3/D3s at 12 megapixels to maintain a large pixel size for better light gathering, Canon continues to move resolution up while tweaking other aspects of their camera such as using Dual DIGIC 4 image processors (1D IV) and putting larger microlenses over the pixels (7D).

So while the bump to 16MP means greater resolution for the Mark IV, it also means smaller pixels on the camera's APS-H (non-full-frame) sized, CMOS sensor. The Mark IV's sensor has a 5.7-micron per pixel size compared to 8.45 microns for the three full-frame Nikons.

It's a bit of an apples-to-oranges comparison though because there are many sports photographers who like the 1.3x lens magnification of an APS-H sensor to get them closer to the action. (There are also some who prefer full frame.) It is worth noting though that the 10-megapixel Mark III had a pixel size of 7.2 microns and I found that three-year-old camera to be a better low noise/high ISO performer than the Mark IV.

It's also worth noting that in my testing, the 9-frames-per-second D3s (reviewed in January 2010 issue of PDN) blew the Mark IV away when shooting at ISO 6400 and higher. But before all those Canon fans out there start hating on me, there's a trade-off to having bigger pixels in the D3s. There are also less of 'em and if you plan to do any major cropping of the images you shot with the D3s, you're going to find 12 megapixels of resolution a bit restrictive. With the Mark IV, I was easily able to crop a 14-bit RAW image of a player going under the basket for a reverse lay-up even though I was on the other end of the court with the lens pulled back when I took it. The same went for isolating a one-on-one scoring chance in the hockey game from a larger image of the rink.

There's also a lot more high-quality noise reduction software on the market now than there was three years ago so the noise you might see at ISO 6400 with the Mark IV is easily removable with Noise Ninja, Noiseware or many other programs.

The one caveat is with skintones which I've always had problems correcting for noise without producing a doll-like look. And if there's one major red flag with the Mark IV it's noise in the skintones at ISO 6400 and above. I saw ruddy, red noise in many of the players I photographed in all three sports. In contrast, I had very few similar problems even at ISO 12,600 with the D3s.