Nikon D7100 chính thức ra mắt tại Mỹ
http://reviews.cnet.com/digital-came...-35618194.html
https://www.dropbox.com/sh/qbpznb7ll5qipya/jiG7R-BZJN
On the surface, the long-overdue update to the Nikon D7000 doesn't look like a huge advancement, but its replacement, the D7100, seems to have several subtle -- and a few not-so-subtle -- enhancements that have the potential to make it a compelling option in an increasingly competitive crowd.
Most interesting: though it has the same resolution as the D5200, the D7100 uses a new and different sensor that lacks an optical low-pass filter (OLPF), aka an antialiasing filter, much like the Pentax K-5 IIs. Dropping the filter is intended to increase the sharpness of the native images without introducing the types of artifacts you get when sharpening in post. The tradeoff tends to be increased moiré, which the camera can usually address adequately for stills but less so for video. Unlike Pentax, which offers a more traditional OLPF'd version, Nikon's putting all its pixels in one basket and offering just the one model -- for now, at least. (Not a clue what I'm talking about? Try reading this primer.)
The sensor has improved readout speed over the D7000, which Nikon attributes to a more efficient design rather than more output channels, and improved noise reduction in part because of an upgrade to the current Expeed 3 image-processing engine
ncreased sharpness is the goal with the viewfinder and LCD as well. The optical aspects of the viewfinder are effectively the same, but the readout now uses an OLED display for higher-contrast text. The LCD's not articulated, but larger and much higher resolution.
Two notable improvements that Nikon claims to have made to the autofocus system include center-point sensitivity up to f8 and faster (compared with f5.6 for the D7000), a big deal for serious telephoto shooters, and improvements to the contrast (Live View) autofocus to ameliorate that annoying pulsing that appears when focused on a stationary subject during movie shooting.
The company has also added an intriguing spot-white-balance feature, available only in Live View mode. It sounds nice, but it'd be great if it could act like an eyedropper instead, sort of a quickie way to pick a color temperature to calibrate against. Other tweaked features include a two-shot, tripod-free automatic HDR and expanding the exposure bracketing to up to 5 shots + / - 3 EV.
While I'm not a big crop mode user, Nikon's introducing a 1.3x crop mode for an effective 2x crop factor (Nikon's math, not mine), producing a 15.4-megapixel image. In that mode, continuous-shooting speed rises to about 7fps and you gain a 1080/60i/50i movie mode.
Nikon promises improved performance, a no-brainer after three years. The real questions are will it be significantly faster than the D5200 and will the OLPF-free image quality be gotta-have-it better. It's also important to note that the 7D is quite old as well and both it and the SLT-A77V are likely to be replaced this year. Plus, Nikon's keeping the D7000 around for an unspecified period -- still a great camera -- so you've got to watch for price drops there.
When the D7000 shipped, Canon and Nikon were pretty much the only games in town for this type of camera, but in the interim, Sony and Pentax have developed formidable options with which Nikon needs to contend.
Nikon also announced a price-and-availability-tbd hot-shoe-based über remote tranceiver to work in conjunction with the rest of its wireless remote accessories. It operates in the 2.4GHz range up to 394 feet, and you can use another unit to relay beyond that, and can control up to three channel groups of up to 64 cameras each.
