Canon and Nikon have now both released their “high-end entry” DSLRs incorporating essentially everything they know about sensors, image processing, video, and what have you in an entry-level body. The big differentiators between $799 (for the D5100) and $1799 (for the 7D) are viewfinder size and accuracy, fairly abstruse things like micro-focus adjustment, “pro” features such as weather sealing, and marginalia such as continuous shooting speed and buffer size**, and number and type of autofocus sensors. Nikon has even included 14-bit RAW support in the D5100 (so its Dx0mark sensor score may equal or exceed the D7000’s, whereas the D5000 was slightly outscored by the D90).
This essentially marks the point at which Nikon and Canon have given up trying to use basic image quality as a differentiator between APS-C models. (Ken Rockwell has been arguing for years that Nikon’s best IQ — modulo sensor size — is always found in its most recent camera, regardless of price, unless it’s the D3000). But Nikon and Canon now aren’t even using megapixels or dynamic range* as a differentiator for imbeciles and enthusiasts — respectively — now. You can compare them here — this should link to dpreview’s D5100 High ISO page — to my eye, the D5100 is as good as the D7000 and K5, and better than every competing APS-C or Micro-four-thirds camera.
* Note that while Canon has offered 14-bit RAW support for years as standard feature throughout its range, the measured dynamic range has lagged behind Nikon’s 12-bit pipeline in actual testing.
** According to Nikon’s product information (unless it’s changed since I linked it) the D5100 has a 16 frame RAW shooting buffer. This would make its shooting buffer larger than the D7000’s (and buffer size is/was perhaps the single biggest criticism of the D7000).
Not coincidentally, the low-end cameras in both ranges are now, unambiguously, the best DSLRs offered by either vendor for shooting video. The D5100 even supports 1080p30 , which begs the question as to whether the D7000 will get a firmware upgrade to match it.
So, that’s the line in the sand. From now on DX cameras will compete, as did their analog forebears, on user experience, something neither Canon nor Nikon are really much good at.
Aside: Pentax seems to be more thoughtful about DSLR design than either Nikon or Canon. (It also does a better job of delivering enthusiast lenses.) For example, Pentax introduced an exposure mode where the photographer picks Aperture and Shutter Speed and the camera picks ISO (which is so obvious) which the others haven’t picked up on. Similarly I believe there’s a program mode where one dial selects ISO and the other works like the dial in Program (or “Professional” as Rockwell puts it) mode — adjusting Aperture and Shutter in opposite directions. Both modes make more sense than any exposure mode on a Canon or Nikon.