วันเสาร์ที่ 28 กรกฎาคม พ.ศ. 2555

Nikon D5100 Reveiw



Nikon D5000 12.3 MP DX Digital SLR Camera with 18-55mm









Nikon started the D-SLR video recording revolution back in 2008 with the Nikon D90 ($609.00, 4.5 stars). Thanks to its large, APS-C image sensor, with 370mm² surface area, the video captured by thisdigital camera and its successors was so good that pros have used Nikon D-SLRs to film commercials and movies. The Nikon D5100 ($899.99 with 18-55mm kit lens) carries on that tradition, and adds continuous autofocus during video recording, a high-res, articulating LCD, a microphone input, and top-notch in-camera effects. With its unbeatable feature set and price, the Nikon D5100 dethrones the Canon EOS Rebel T2i ($899.99, 4 stars) as our Editors' Choice under-$1,000 D-SLR.

Design
On the outside, the D5100 looks like virtually every mid-price D-SLR Nikon has put out in the past few years. They're all very luxurious looking and substantial-feeling (The D5100's body weighs 1.2 pounds, and with its included 18-55mm lens, the camera weighs 1.8 pounds). You get switches, dials and levers galore, to get you quickly into almost any mode. There's also a directional pad for speedy menu navigation.
The Nikon D5000 ($729.99, 4 stars), the D5100's 2009 predecessor, used a low-resolution LCD that really wasn't in line with its competition. The LCD on the 5100 is a huge leap forward. The 3-inch LCD is filled with 921K dots, which means it's much crisper and sharper than the D5000 and the less-expensive D3100 ($499, 4.5 stars), which have LCDs filled with just 230k dots. When you're trying to frame shots with lower-res LCDs, it's tough to tell if your images are actually in focus. That's definitely not a problem with the D5100.
Also, the display swings out and spins up to 270 degrees, so you can use it to frame shots even when you're holding the camera above your head or at waist level. Many other cameras that offer an articulating LCD, like the Canon EOS 60D ($1,188.95, 4.5 stars), aren't particularly useful, because whenever you engage Live View (which uses the LCD as a viewfinder) autofocus slows to a crawl. The D5100's autofocus is much faster than most traditional D-SLRs, but it's not the fastest. The Sony Alpha A580 ($1,000.39, 4 stars) is one of only a few D-SLRs that can deliver speedy autofocus in Live View mode; it's actually faster than the D5100, but it can't be used during video recording (more on this later).
The user interface on the D5100 doesn't differ much from other Nikon D-SLRs. It's pretty straightforward, and text and graphics in the menu system look particularly good because the LCD is so sharp.


Performance
Since the Nikon D5100 is a traditional D-SLR, when you're using the optical viewfinder to shoot it's blazing fast. The camera powers up and shoots in just 1.4 seconds, and after that, it can capture three frames per second in continuous shooting mode. When using the optical viewfinder you get fast phase detection autofocus and virtually no shutter lag (the time between shutter press and image capture). Shooting speed slows down considerably in Live View, but it's still faster than most D-SLRs are in that mode.
In the PCMag Labs, we use the Imatest suite to objectively evaluate image quality. Under its cleanest conditions (at ISO 100) the D5100 delivered a center-weighted average of 1,860 lines per picture height—a result higher than 1,800 is very sharp. At the same ISO, however, the Canon T2i was even sharper, scoring 2,296 lines. In terms of noise, if Imatest reads less than 1.5 percent noise in an image, it won't be visibly grainy. The Canon T2i kept noise levels below 1.5 percent up to and including ISO 3200, which is excellent, but the Nikon D5100 takes things to the next level. It can go to ISO 6400 and stay below 1.5 percent, which means this camera will perform very well sans flash in low-light shooting situations.


Video Recording
Video produced by this camera is just like its still images—gorgeous. Because you have a huge image sensor, video is sharper, shows less noise, and has a larger depth of field and dynamic range, when compared with a dedicated camcorder or compact camera, which have smaller image sensors. You can simply put the D5100 in Auto mode, or manually adjust the shutter speed (to control the level of blur in your footage) or the aperture (to adjust the depth of field). You can capture video in 720p or 1080p at 24 or 30 frames per second, though enthusiasts might be disappointed since there's no option for capturing 720p at 60 frames per second.
The D5100 can also provide much faster autofocus while in video recording and Live View mode (shooting still images while using the LCD as a viewfinder) than its competition. In Live View mode, the Canon 60D averaged 4.24 seconds to bring a subject into focus, and the Nikon D5100's faster contrast-measurement focuses in just 2.41 seconds. The Sony A580 dominates both of these in live view shooting, though.
Faster autofocus performance means the D5100 can provide continuous autofocus during video recording. (The Nikon D3100 and D7000 also provide faster autofocus, which makes any of the three the easiest experience for recording video on a D-SLR.) That's not to say the experience is flawless, but it's the closest a D-SLR has come to camcorder-like shooting. With any other D-SLR, if the camera or your subject moves, you'll lose focus, and to get the subject back into focus, you have to either turn the focus ring manually or hit a dedicated autofocus button. The Nikon D5100 can lock on and track subjects and faces automatically, without any action from you.
The video recording experience is the easiest of any D-SLR, but there're still a few drawbacks, and a few products that do a better job at recording video. Anytime the D5100 refocuses, you'll hear a little grinding noise from the autofocus motor in the lens. The only way to avoid this is to focus manually or use an external microphone (Nikon makes the ME-1 microphone, which mounts to the camera's hotshoe).
If you want a more manageable video experience but want a big image sensor for dazzling video, there are a few other cameras worth considering. The Sony Alpha 55 ($849.99, 4 stars) looks like a D-SLR, but the inside has been redesigned so it can access its phase-detection autofocus system during video recording mode (its continuous autofocus can refocus in less than a second). The downside, though, is that it lacks any optical viewfinder and still uses lenses that make noise when continuously autofocusing. The Olympus E-PL2 ($429.99, 4 stars) Micro Four Thirds camera and the Editors' Choice Sony NEX-3 (512.16, 4.5 stars) are small-body cameras that can continuously autofocus, and their lenses have silent irises so you never hear any noise when refocusing. The Sony NEX-3 and Alpha 55 both use large 370mm² sensors like the D5100, but the Olympus E-PL2 uses a smaller 225mm² size sensor.

If you're adventurous with creative tastes but don't want to knock yourself out in Photoshop or Final Cut, the D5100 has some great built-in effects. I've seen a few of them in compact cameras, but rarely in D-SLRs. Some of my favorites are Fisheye, Selective Color, and Color Sketch, which gives your photos and videos a comic book look. The camera can also create High Dynamic Range (HDR) photos by merging under- and over-exposed images of the same shot. The Miniature Effect, which makes your subjects look like miniatures models, is also pretty cool. Typically the miniaturizing effect requires a tilt-shift lens that can manipulate the depth of field, but the D5100 can simulate this effect digitally on the fly.
The D5100 has the same inputs and outputs as the D3100, plus a microphone input, which is key if want to use an external mic to avoid capturing noise from the lens while uses autofocus during video recording. There's a mini-HDMI port so you can plug your camera right into your HDTV to view photos and videos. The USB port is proprietary, so you can't replace the bundled cable with a standard USB cable. The camera writes media to SDXC and SDHC cards, but you'll need at least a Class-4 card to shoot video, and a Class 6 card to take advantage of the camera's fastest still-frame captures.
Overall, if you want an easy-to-use D-SLR that offers solid features, is lightning fast, and can produce fantastic photos and video, the Nikon D5100 is the perfect choice. If you want the simple video recording but don't mind a lower-res LCD and lack of microphone input, you could save $200 and grab the Nikon D3100. And if you're a Canon fan on a budget, our former Editors' Choice, the EOS Rebel T2i is still a very respectable, affordable choice. But its balance of features, performance and price, however, make the Nikon D5100 our Editors' Choice for an under-$1,000 D-SLR.