It's been rumoured for a long time and now it's finally here. We are, of course, talking about the Nikon D7100 - the company's latest APS-C DSLR camera that looks to give even the D300S a run for its money. Pocket-lint had a play with a pre-production model ahead of the official unveiling to see how this new APS-C champion fared.The D7100's specs read rather well. It's laden with some of the tech that can be found in the top-spec, full-frame Nikon D4 model but at a fraction of the price, coupled with other brand new features such as a newly developed 24.1-megapixel CMOS sensor which - wait for it - has done away with the anti-alias filter, just like the Nikon D800E model. Only the D7100 doesn't come in two flavours: none of the models is equipped with the filter.READ: Nikon D4 reviewNikon claims that at such a high resolution and where pixel density crosses a certain threshold - although, when questioned, declined to comment where that threshold was - the need for an anti-alias filter has little use in most given shooting situations. Sounds as though it's being treated as the camera's equivalent of an appendix - and Nikon doesn't think you'll miss it. Will it leave a scar?As it stands, we're not yet sure. The low-pass filter's function is to filter out certain frequencies of light while slightly diffusing the light before it lands on the sensor to provide a more generalised, yet softer, read that can be better interpreted to omit colour inaccuracies or moire. The D7100 will still have the wavelength-limiting filters, such as an IR filter, so it's not as though the full filter unit has been removed, it's just that diffusion no longer takes place which, in turn, should result in a sharper final image.The pre-production sample we got to play around with wasn't loaded with a card and we weren't allowed to leave with any shot-on-site image samples either. We'll have to await the full and final production sample to give it a thorough testing.When Pocket-lint questioned Nikon about the move the company said that "the positives outweigh the negatives" - which doesn't necessarily mean some shots won't run into issues. We're yet to see the results so it'll be interesting to see how the D7100's processing resolves images, but the camera uses a standard Bayer colour array - nothing new-fangled like, say, Fujifilm's X-Pro1 colour filter arrangement.READ: Fujifilm X-Pro1 reviewThe D7100's sensor itself is the same base as that found in the Nikon D5200 but has been "newly developed" with more advanced, faster circuitry to outperform the mentioned mid-level model. Paired with the Expeed 3 processor and the D7100 can produce images from ISO 100 through to ISO 6400 and also supports Hi1 and Hi2 settings with equivalent values of ISO 12,800 and 25,600 respectively.As we spotted in our Nikon D5200 review there were signs of banding in shadow areas of raw files, so we hope the D7100's updated development will iron out any issues we've seen with the mid-level model.READ: Nikon D5200 reviewElsewhere the D7100's only gone and nabbed the same 51-point autofocus system as found in the Nikon D4. Yup, the full 51-point, 15-cross-type, sensitive to 2EV and f\/8 system adapted for the APS-C model. It'll probably bring a tear to the D300S's cameray eye. Or should that be lens?We put the autofocus to the test in a fairly dim room - that's why our sample pictures in this article are a touch noisy - and it flew without any qualms zipping into focus on faces, furniture and fittings. Sounds like an episode of Grand Designs - but this was much more exciting.Both focus types and area modes can be accessed via the AF switch to the front left side of the camera, including 5, 9, 21 and 51-point options through AF-S, AF-C, AF-A and 3D tracking options. Impressive for this level. We like.But there's another feature that made the AF system all the better in our minds. There's a 1.3x crop function that, well, does exactly what it says on the tin - it crops into the frame to produce 15.4-megapixel images with the benefit of an increased telephoto equivalent. But it also means the 51-point system is far, far wider-reaching across the viewfinder frame which means little-to-nothing will be out of reach from the focus point array.It also means a 7fps burst mode is possible - one better than the 6fps burst that's available in the full-resolution 24-megapixel mode. In other camera systems that employ a similar tele-zoom function option, such as the Sony Alpha A99, for example, there isn't the option to shoot raw files. In the Nikon, however, this is possible - something we've been waiting on for a while.READ: Sony Alpha A99 reviewIn use we found the D7100's 100 per cent optical viewfinder to be large and bright with a good feedback display of focus points. Reaching for the rear d-pad to move individual point selection felt natural, while the new Organic EL display to the base of the viewfinder is super bright with white text that's easy to read.The camera's rear LCD screen, while fixed to the body rather than on a variable bracket, also sees updates. It's not only 3.2-inches in size, but now also features a new white layer for a brighter view to withstand stronger light sources. This 1000:1 contrast ratio WRGB panel is 1229k-dots which, while it may sound higher resolution than the usual 921k-dot screens, isn't the case - each of the white, red, green and blue layers amounts for one "dot" each, so each four amount to a "pixel". In other terms it's still a VGA panel with a 640 x 480 pixel resolution, it just happens to be larger, brighter and, well, just better. We're yet to see it outside in the big, bright world - something that a British summer should help with when we get hold of a final review sample closer to launch date. Assuming, of course, that it doesn't rain cats and dogs for six months in 2013.Design-wise there are other more subtle changes to be seen and felt too. The imprint of the D7100's body is smaller than the D7000, hence the need for a new optional MBD-15 battery grip to fit to the camera's shape, despite both models - as well as other Nikon DSLR units - utilising the EN-EL15 battery type. The mode dial now features a press-and-hold lock button and is a different, more prominent texture.The D7100's magnesium alloy top and base panels are not only tough, but the camera is also weather-sealed to the same standard as that found in the D800 model, according to Nikon. It's a toughie.READ: Nikon D800 reviewAnother addition is a new "i" button on the rear to the bottom left - it makes up a total of five buttons arranged to the side, compared to the four as found on the D7000. This new button brings up a full-screen menu to quickly dive in and out of, while in live view it brings up a side-menu that's superimposed across the preview.Movie-wise there's the option to shoot 1080p at 30, 25 or 24 frames per second with progressive capture or 50\/60fps using interlaced capture. A mic input and headphone output also feature. However we're not sure how the removal of the anti-alias filter will effect video results - with no cards in the camera it wasn't possible to shoot clips to take an early look.And on to the numbers: the D7100 will be available at the tail-end of March priced \u00a31100 body only or \u00a31300 with the 18-105mm VR lens. There's a lot of tech on offer here and, assuming the filter-free system delivers the goods, this sounds like the enthusiast DSLR to beat for 2013. It's got us scratching our chins as to whether camp Canon will make a DSLR appearance in the immediate future.