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Nikon D3100 Gordon Laing, November 2010
 

Click here to find out about the Nikon D3100's Lens, AF, sensor and drive modes

 

Nikon D3100 Movie Mode

The Nikon D3100 becomes the latest DSLR to feature an HD movie mode. It's a major upgrade over its predecessor which didn't even offer Live View, let alone video capture. This also gives the D3100 a crucial advantage over Canon's entry-level EOS 1000D / XS, which doesn't offer a movie mode, although it's important to remember the D3100 is priced closer to the EOS 500D / T1i which does have video.

Nikon was the first company to offer HD video recording on a DSLR, with a 720p / 24fps / Motion JPEG mode on the D90 back in October 2008. The movie capabilities of the D90 were duplicated for the D5000 and the D300s after that, with only minor upgrades, such as an articulated monitor on the D5000 and an external microphone input and in-camera cropping on the D300s.

While Nikon's core movie capabilities essentially stood still for two years though, Canon took the ball and ran with it. Now models from the affordable EOS 550D / T2i upwards boast 720p and 1080p at a choice of frame rates, external microphone inputs and longer recording times, while the EOS 5D Mark II has become the darling of independent film makers, commonly pimped-up with pro accessories and used on high profile shoots. So while it's fair to say Nikon started the ball rolling for DSLR video, Canon quickly swooped-in and captured the professional market.

As such it's not surprising to find Nikon revamping the movie mode capabilities and experience on the D3100. Previous Nikon DSLRs offered a best quality movie mode of 720p at 24fps, but now the D3100 offers the same resolution at the choice of 24, 25 or 30fps, while crucially adding a new Full HD 1080p mode at 24fps.

     
     

Nikon's also ditched the previous Motion JPEG encoding which may have been easy to edit, but suffered from larger files and HD recording times limited to five minutes. Now it uses the same H.264 format as Canon and supports clips up to ten minutes each (regardless of resolution). Most impressively of all, the D3100 becomes the first DSLR to attempt continuous autofocusing while filming. There's lots to discuss below, but before we launch into the fine details, let's check out our first clip.

 


Nikon D3100 sample video 1: Outdoors, handheld panning and zoom with DX 18-55mm VR
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In the handheld clip above the first thing to notice is the lack of vertical streaking around the sunlight reflections on the water – this is a benefit of a camera with a CMOS sensor. But if you're playing the file with audio, you'll almost immediately notice a faint squeaking or scratching in the background. This is the sound of the kit lens constantly being refocused by the D3100's new AF-F continuous autofocus mode, and it's quite audible on this clip.

Unfortunately in this example, the continuous autofocus isn't doing a great job either, regularly searching for a subject with sufficiently strong contrast for it to lock onto. So while the actual video quality itself is fine, the continuous AF option hasn't performed so well in this example; indeed disabling it would have probably produced better results. But before you write-off the D3100's AF-F mode, check the clips below as it can work reasonably well under the right conditions. PS – at the end of the clip we've attempted to smoothly zoom the lens in and out, and as usual this is an almost impossible task with a handheld DSLR.

 
 
 
 
 
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With this first example out of the way, let's take a look at the specifics. Like previous Nikon DSLRs with video capabilities, the D3100's Movie mode works as an extension to Live View. So first you'll need to enter Live View by flicking the new spring-loaded lever on the back of the camera. Then to start recording, simply press the red button in the middle of the lever, before pressing it again to stop.

Unlike Canon's latest models, there's no dedicated manual exposure mode, and the D3100's instructions make no mention of any aperture or shutter control. We do however understand the D3100 is similar to earlier Nikon DSLRs, whereupon an aperture selected in manual or aperture priority prior to entering Live View, will be adopted by the movie mode. Once you're in Live View though, the aperture cannot be changed for movies. Nikon tells us the ISO can also be manually set prior to entering Live View, but clearly there's an automatic override to avoid shutter speeds that are too slow. Speaking of which, the shutter speed in the movie mode is automatic.

The D3100 offers five movie quality options which can be adjusted in any mode: 1080p at 24fps, 720p at 30, 25 or 24fps, and a 640x424 option at 24fps; pros will be relieved to discover the 24 and 30fps modes actually record at 23.976 and 29.97fps to match other pro equipment, but unlike Canon's 550D / T2i upwards, there's no additional options to record 1080p at 25 or 30fps, nor 720p at 50 or 60fps.

As stated above, the maximum recording time in any of the D3100's quality modes is ten minutes, or when the file reaches 4GB in size. You're looking at about 2.3MB per second (or around 140MB per minute) in the best quality 1080p mode, which means the ten minute limit will be reached with a file measuring around 1.4GB.

Nikon recommends using a Class 6 card or quicker for HD movies; we used a Lexar Professional 8GB 133x SDHC card in our tests with no problems, and confirmed the ten minute limit with a 1080p file measuring 1.29GB. Note Canon's HD movie modes are much more memory-hungry, consuming almost two and a half times as much data at 330MB per minute thanks to higher bit rates. That said, there's no ten minute limit on the Canons, so their 4GB file size will be reached after around 12 minutes of HD filming.

Audio on the D3100 is recorded in mono only, using the built-in microphone; sadly unlike the Canon 550D / T2i upwards, there's no external microphone input, and unsurprisingly no manual control over audio levels either. The video and audio are encoded using H.264 and stored in a Quicktime MOV wrapper – this is the same compressor as Canon, but used at a lower bit rate for smaller file sizes. Like Canon's MOV files, we found VLC Player proved best for playback under Windows.

You can take a photo with the D3100 while filming, but there's a pause between pressing the button and the image being captured – and it will also stop your recording.

Nikon D3100 sample video 2: Outdoors, tripod-mounted pan with DX 18-55mm VR
Download the original file (Registered members of Vimeo only)

In our second clip, above, we've mounted the D3100 on a tripod, disabled VR and AF on the kit lens and smoothly panned from left to right. Despite being a little over-exposed (like the same shot in our Outdoor results page), there's plenty of detail here, and we've also paused at the start in case you'd like to grab a frame for closer analysis. We also filmed the same sequence moments later in the three 720p modes, so if you'd like to compare them, check out our 720p / 24fps, 720p / 25fps and 720p / 30fps clips.

 

Nikon D3100 sample video 3: Indoors, dim light, handheld pan with DX 18-55mm VR
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Moving on, our third clip above was filmed handheld in a relatively dim bar with both VR and AF-F enabled, although thankfully the latter doesn't appear as confused by the subject matter as in the first clip.

 
 

It's fair to say lots of people had high hopes for the new Full-time servo AF-F mode on the D3100 and its more sophisticated counterpart the D7000. In theory this allows both cameras to continuously autofocus while filming, a capability which has eluded traditional DSLRs to date. For example, while Canon's latest DSLRs support autofocusing while filming, it's a Single AF operation which is initiated by hand and takes several seconds to lock-on thanks to the leisurely contrast-based AF system. Theoretically you could just keep forcing a Canon DSLR to repeatedly perform this process in an attempt to keep the subject sharp during a clip, but it wouldn't look pleasant with constant visual searching, not to mention the sound of the lens doing it.

If you've watched the first clip above though, you'll know this is effectively what's happening with the Nikon D3100's AF-F mode, albeit the difference here is the camera initiates the AF process, not the photographer. The D3100's AF-F mode works exactly the same way in movies as it does within Live View. It immediately checks the selected AF area and if it's not sufficiently sharp, it'll use the contrast-based AF system to focus on it. Depending on the subject though, this could take an average of two seconds each time with the lens typically searching back and forth at least twice. If your lens has audible autofocusing, like the DX 18-55mm VR kit lens, you'll also hear this squeaky scratching sound recorded quite clearly in your movies. And if the subject regularly moves, the camera will keep trying to lock-onto it, which means your video could suffer from a lot of visual searching, and of course the sound of it too. Our next clip better illustrates how the system works and what kind of response you can hope for.

Nikon D3100 sample video 4: Indoors, continuous AF test with DX 18-55mm VR
Download the original file (Registered members of Vimeo only)

Our fourth clip, above, deliberately put the new AF-F mode to the test. Here we moved the camera around, pointing it at various subjects near and far to see how the continuous autofocus coped. At first it doesn't seem to do very well, refusing to focus on the coffee cup until the composition was readjusted. But give the D3100 some sharp edges for its contrast-based AF system to lock-onto and it can actually do quite a good job. Sometimes the focusing searches a little, but at others it feels more confident as it locks-onto the desired subject.

Indeed as the clip progresses, it's hard not to be quite impressed by the AF-F mode as it succeeds more than it fails. It may not be as consistent as a consumer camcorder, nor as confident as the phase-change AF on the Sony Alpha A33, but the D3100 still manages to keep the subject mostly focused as the composition changes, while the ambient background sounds in this clip mostly mask the kit lens's AF motor. This is an impressive capability for a camera that only has a contrast-based AF system at its disposal while filming (along with the challenges of a shallower depth-of-field than a camcorder); remember Canon's DSLRs don't even attempt to continuously autofocus while filming, making this clip impossible without constant manual adjustments.

Nikon D3100 sample video 5: Outdoors, continuous AF tracking with DX 18-55mm VR
Download the original file (Registered members of Vimeo only)

In our fifth clip, above, we've given the D3100 a more predictable subject to track with its continuous AF. We zoomed the kit lens to 55mm, selected the D3100's central AF point only, and kept it positioned over the Skyline logo on the cable car as it steadily approached.

Like most contrast-based AF systems, the D3100 searches back and forth as it attempts to lock-on, and this is quite visible at several points during the clip. This is undoubtedly off-putting, but to be fair, the D3100 does manage to keep the logo relatively sharp throughout the clip, even when it's only a meter or so distant. Once again this is something which would have required constant manual focus pulling on a Canon DSLR. So while the D3100's continuous AF during filming may not live up to the experience of a consumer camcorder (nor the unique capabilities of the Sony Alpha A33), it remains a very impressive attempt given the available resources.

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That said, for subjects where the soundtrack was critical or the subject remained mostly at a fixed distance, we switched the D3100 to manual (or single) focus. When AF-F works well, it's pretty neat, but more often than not it spoilt our clips with its constant searching. Indeed once you've seen and heard the effect of the kit lens constantly search back and forth on clips, you'll find it some relief to simply switch it off.

As for the quality, the 1080p mode looks similar to comparable DSLRs, although complex scenes will benefit from the higher bit rates used by Canon. That said, the D3100, like all DSLRs tested to date, is equally susceptible to the dreaded jello effect when the camera's wobbled or twisted. Some will also find it a shame there's no alternative frame rates for 1080p at 25 and 30fps. We understand independent film makers will be most interested in having 24fps, but there's plenty of other users who'd have found 25 and 30fps options better for integrating with existing camcorder footage. It's also a little inconsistent to suggest 24fps is the professional's choice, then offer 25 and 30fps at 720p. And lest we forget, this is an entry-level DSLR, which is unlikely to be used for many pro projects.

Two things which really hold the D3100 back for pros and enthusiasts alike are the lack of a microphone input and definitive manual control over exposures. Both are offered on the higher-end D7000 though, albeit again with 1080p only available at 24fps.

Overall though the D3100's movie mode is pretty respectable, but if you ignore the AF-F mode (which you probably will on most of your clips), then models like Canon's EOS 550D / T2i upwards are ultimately more capable. They may effectively become manual focus only, but offer 720p at higher frame rates, 1080p at the choice of three rates, higher resolution screens, external microphone inputs for considerably superior sound quality, higher bit rates for better video quality and slightly longer maximum clip lengths. Alternatively if decent continuous autofocus is your priority while filming, then Sony's SLT A33 becomes your top choice.

Now find out how the D3100 compares against its rivals in terms of image quality in our results pages and sample images gallery. Alternatively if you've already seen enough, head straight to our verdict.


 

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