Nikon d3100

For a more budget DSLR the Nikon D3100 has plenty of movie features on offer: it's the only sub-£500 model with Full HD 1080p recording at 24fps 'cinema' mode and has a continuous autofocus option too. There's even a 30fps option at 720p resolution.

However, there're words on paper and then there's the reality of how a function truly operates. With the D3100 it's a bit of a mixed bag.

Although the camera's new live view AF system is faster than any other Nikon DSLR it won't outsmart the likes of a compact system camera's speedy autofocus for example, and this reveals itself when recording videos of moving subjects. While the D3100's autofocusing speed is certainly good, the camera hasn't quite eradicated the over- and under-focusing issues that show just prior to attaining final focus.

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The D3100's AF-Area modes - that allow the user to select how and where the camera will focus - are more comprehensive than many competitor cameras. Subject Tracking AF is designed to track moving subjects by 'recognising' them and their movements on screen, while Face-Priority AF is of a similar ilk but can auto-recognise facial features (as represented by a boxed area around the face) and then focus on them. Both have a lot of potential but neither stop the slight mis-focusing issue.

As well as a wide, automated focus array there's also a very cool user-defined AF mode (with a rather conventional 'Normal-area AF' namesake) where the focus point, represented by a small rectangle, can be moved to any point of the screen using the d-pad. It's rare a camera can offer edge-to-edge focusing across the entirety of the screen, but even better than that you get to choose exactly where focus takes place.

During capture it's possible to adjust the exposure compensation with the results shown live on screen. Although it's possible to change the aperture value displayed on screen during recording this has no correlation to the actual aperture - the camera automatically sets this itself on each occasion, so the D3100 repertoire lacks any manual video modes.

Performance

Using the H.264 codec the D3100's MOV files stream at around 20mbit/s to create files of 150MB per minute. The compression's a little on the high side and detail isn't as forthcoming as it should be. Add to this muted colours and the final files don't wash quite as well as the specification would have you believe.

Yet, of course, the D3100's focusing controls are beyond many other DSLRs so it's a case of weighing up potential use against final quality.

In terms of audio the D3100 is a lot like the Canon 1100D. The on-board mono microphone captures decent quality audio, but any sounds from the lens autofocusing are amplified and prominently picked up in clips.

Nikon D3100 key video spec

Approx street price: £459 with 18-55mm kit lens
Sensor: APS-C sized sensor (1.5x magnification)
Resolution: 1080p capture (1920x1080px) maximum resolution
Frame rate: 24fps (30fps at 720p resolution)
Compression: H.264 video compression

File format: Linear PCM audio and MOV file format
Exposure mode: Programme shooting mode
Focus modes: Full time (AF-F), Single (AF-S) and Manual (MF) focus options
Connectivity: HDMI-C and mini-USB AV out ports