老外告诉你，为什么不能买尼康 D5100和D7000

We told them but they didn\\\'t listen! The D5100 has all the same live view problems as the D7000, one bug has even been around since the D300 and they haven\\\'t fixed it. The D7000 meanwhile just had a firmware update, which doesn\\\'t fix anything.

The purpose of this article isn\\\'t to slam Nikon but to draw attention to exactly what needs fixing. It is clear that Nikon\\\'s philosophy to live view and movie recording so far has been that this function is only there to facilitate the point & shoot ease of use like a compact, because in terms of manual control their live view is as bad for stills as it is for video.

Problems affecting both stills and video

• In P/S/A mode the display accurately simulates exposure like every other camera, but in M (manual) mode it gives up
• To compound that issue, there is no exposure meter so if you use manual shutter, ISO or aperture in live view you have to guess what the exposure is going to look like. Simply crazy.
• Due to a bug present since the D300 the camera won\\\'t apply the aperture change via the body to the lens if you are changing the aperture whilst in live view mode, even though the information display on the LCD shows the aperture value changing, the camera always uses the last aperture value set whilst using the optical viewfinder.

Problems only affecting video

• The old D300 bug also affects movie recording - when you enter live view to record a movie, you can adjust the aperture but the camera will ignore it. Take a shot at F8 and then enter live view, set aperture to F1.4 and hit record - the manual states it should record at F1.4, the screen is telling you \"F1.4\" and yet the movie is being shot at F8!
• Critically shutter speed and ISO are controlled automatically by the camera in live view and movie mode, although pressing and holding AEL for the duration of the shot prevents them from changing. Yes shutter and ISO are adhered to in live view mode, just not by the display or movie. For example you can set ISO 100 and 1/30 and hold AEL whilst hitting the record button but it\\\'s awkward and means you have to have your hand on the camera even when recording.
• Automatically set high shutter speeds give an unusable picture under most PAL region electric lights in 24p mode, and generally a higher shutter speed than 1/50 causes an electronic \\\'action\\\' stutter over motion instead of the smooth cinematic look of an optimal shutter speed
• Since there is no dedicated movie mode on the dial, the D5100 and D3100 only applies a 16:9 crop on the display once recording is activated, so you have to frame the shot in 3:2 and guess where the top and bottom of the frame is. The D7000 has a very faint grey bar overlay but only when a lot of other jazzy shooting info is displayed alongside it, obscuring the image.
• No 25p on the D3100 or D7000 (the camera is unusable by European / PAL region broadcasters and professionals). No 60p. Offered modes on the D5100 are 1080/30p/25p/24p and 720/30p/25p/24p.
• Despite offering the same AVC codec as AVCHD, the maximum run time per clip is just 10 minutes and the high bitrate is there to compensate for a lack of sophistication in the encoding process, i.e. no space saving predictive frames or b-frames. It doesn\\\'t make for a better image just stops it from falling apart altogether.
• The image has heavier moire and aliasing than the GH2
  

These problems affect all Nikon DSLRs whether cheap or expensive. The same problems present in the D3100 for example also affect the D7000. The only area where the D7000 differs is that the movie mode responds to manual ISO and shutter speed control without the need to hit AEL - although the live view display still does not - no manual exposure simulation or meter.

Despite these problems which are a waste of a good camera, Nikon spent valuable R&D time on two features people will never use since the live view and movie experience is so diabolical and buggy - the D5100 has less rolling shutter and faster live AF than Canon DSLRs and an articulated screen. All completely wasted by the firmware problems.

Whilst any camera is capable of nice images, the advantages of the D5100\\\'s slightly better high ISO performance does not make it a compelling alternative to the Canon 600D or Panasonic GH2, the huge pain is not worth the ever-so-slight gain.

So if you like to have fun guessing where the edges of the frame are and what the exposure is, buy a Nikon.

Further reading at DPReview.com