The big news about the Nikon D7100 isn't that it has a 24.1 million pixel sensor - that was fairly predictable - but rather that Nikon has decided to omit the anti-aliasing element from the camera's filter above the chip.
The Nikon D7100, in contrast, isn't available in two varieties and can only be bought without the filter in place.
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Most camera manufacturers use an anti-aliasing filter (AKA low-pass filter) to reduce the risk of interference patterns known as moiré patterning that can occur when an object with a fine texture that's close to the sensor's resolving limit is photographed. You've probably seen this at some point on the television when someone has worn the wrong tie or shirt and a frenzy of lines is created at an angle to the fabric's pattern.
Nikon claims that the pixel density of the Nikon D7100's APS-C format sensor is sufficiently high that there are relatively few occasions when moiré patterning is likely to occur, and consequently no anti-aliasing filter is required. The downside of using a low-pass filter is that it softens the images slightly, and this has to be addressed by sharpening the image post-capture.
Leaving off the filter should mean that the Nikon D7100 is capable of producing sharper images direct from the camera. But how much difference does it make in comparison with the Nikon D5200 and Nikon D3200, which also have 24MP sensors?
Like Nikon's more recent DSLRs, including the Nikon D4 and Nikon D800, the Nikon D7100 has the Expeed 3 processing engine. In combination with the sensor, this enables a native sensitivity range of ISO 100-6400, which can be expanded to the equivalent ISO 25,600 if required.
Despite having the same processing engine and pixel count as the Nikon D3200 and Nikon D5200, the Nikon D7100 can shoot at a faster frame rate of 6fps (frames per second). This trumps the Nikon D5200 by 1fps and the Nikon D3200 by 2fps, making it better suited to sport and action photography.
However, the Nikon Nikon D7100 has another trick up its sleeve that enables things to be pushed a little bit further - a 1.3x crop mode. This is useful if you need to get a little tighter in on your subject and don't want to crop the image post-capture, and it enables the maximum continuous shooting rate to be boosted to 7fps.
Nikon has further boosted the D7100's sport and wildlife shooting credentials with the inclusion of the 51-point Multi-Cam 3500DX AF module, which has 15 cross-type AF points around the centre of the frame. In comparison, the Nikon D7000 has 39 AF points, of which nine are cross-type.
Those who think 51 AF points is a bit excessive can opt to restrict the selection to 11 in single AF mode. As we have seen before with Nikon's high-end DSLRs, in continuous AF mode the camera can be set to track the subject using 51, 21 or nine AF points after you've selected the starting AF point.
Alternatively, there's 3D tracking available in continuous AF mode, which looks at the colour of the subject and attempts to follow it around the frame. However, if you want to keep things simple, the camera can select the AF point for you in Single AF and Continuous AF mode.
The Nikon D7100 is the fifth DSLR in Nikon's lineup to feature an AF system that is sensitive down to f/8. This means that the camera will continue to focus the lens automatically when a telephoto lens and teleconverter combination results in an effective maximum aperture as small as f/8. Naturally you can shoot at smaller apertures than this and use automatic focusing, since it is only the maximum aperture that is the issue.
Like the Nikon D7000, the Nikon D7100 has a 2,016-pixel RGB sensor that provides data to the Scene Recognitions system that guides the metering, white balance and autofocusing systems. You can also take control over the colour of your images via the Picture Control modes (Standard, Neutral, Vivid, Monochrome, Portrait and Landscape) with options to adjust the sharpening, contrast, brightness, saturation and hue of the colour modes.
Nikon has stuck with the same effects modes for the D7100 as those on the D7000, namely Night Vision, Color Sketch, Miniature Effect, Selective Color, Silhouette, High Key and Low Key. We can't see much use for Night Vision or Color Sketch, but Miniature Effect and Selective Color can produce some fun results.
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The downside to these modes is that images are only recorded as JPEGs and there's no option to have a 'clean' raw file. On the plus side, the main LCD screen displays the impact of the effects in Live View mode, and the refresh rate isn't excessively reduced. It's also possible to use the Effects when shooting movies.
On the subject of movies, the Nikon D7100 can shoot Full HD movies and there are ports to connect both an external microphone and a pair of headphones for better sound recording and monitoring.
Movies can be shot in DX mode at 24, 25 or 30p, but when the 1.3x crop is employed it is also possible to record 50i or 60i footage for smoother action or slow motion playback.
The Nikon D7100 is priced at £1,099.99 / US$1,199.95 / AU$1,558 body-only or £1,299.99 / US$1,599.95 / AU$1,849 with an 18-105mm VR kit lens, making it considerably more expensive than the new Canon EOS 700D.