Canon EOS 5D Mark III launched

Three-and-a-half years ago, Canon kick-started the large sensor revolution with its full-frame DSLR, the EOS 5D Mark II. Since then it has been used on numerous TV dramas, such as House, and other productions to achieve shallow depth of field. Now Canon has introduced the 5D Mark III, which addresses most of the Mark II’s problems.

While the 5D Mark III isn’t the huge leap forward that some users had expected, it does have all the video features previously announced for the up-coming EOS-1D X, but at about half the price, and adds a headphone jack for audio monitoring.

It can record using either interframe or intra-frame compression. The interframe IPB AVC H.264 compression is apparently about 31Mbps (according to the Canon USA website figure of 235MB/min - the 5D Mark II was about 38-40Mbps). However, it has been reported elsewhere as 50Mbps (variable bitrate). The ALL-I intra-frame codec has been reported variously as being 78Mbps, 91Mbps (from the 685MB/min on Canon's US site), and even 300Mbps+ (although maybe that was just the recommended specification for the Compact Flash card). It too is a variable bit rate, and also varies depending on frame rate (going to 81Mbps for 720/60p). However, if we take 91Mbps as correct, that is not necessarily sufficiently better than the Long GoP (group of pictures) interframe compression for broadcast work. The BBC/EBU recommendation for minimum bit rate for interframe is 50Mbps, while for intra-frame recording it is 100Mbps (see What makes an HD camera?) - interframe recording is a lot more efficient than recording all the frames individually, although intra-frame should be easier for post production as the computer doesn't have to look at half-a-second's worth of video just to decode a single frame.

It will shoot 1080 at 24, 25 or 30p, plus 720 at 50/60p (at variable frame rates). There has been a lot of griping that it doesn't do 1080 at 50/60p, but there aren't many professional video cameras that do 50/60p at a decent bit rate, so it's a bit much to expect a relatively low-cost DSLR to do it.

According to Canon, “the new full-frame sensor combines with the vast processing power of DIGIC 5+ [processor] to improve image quality by virtually eradicating the presence of moiré, false colour and other artefacts,” which was the principle problem with the Mark II. In the initial videos released by Canon, these artefacts don’t appear to be noticeable (although the sample online videos are too compressed to make an accurate judgement). There still seem to be some rolling shutter effects (jello), but this appears to be much reduced compared to the Mark II.

Other video related changes include the addition of a movie mode switch and a recording button (similar to the 7D), which enables users to begin shooting immediately when movie mode is engaged (and also allows two completely different settings for movie and stills modes), and locks to prevent accidental exposure changes (something that was a paid upgrade for the Mark II). The rear control wheel is now touch sensitive, so you can make light-fingered adjustments as you are shooting without potentially knocking the camera. Users can also check and adjust audio during recording via the camera’s Quick Control screen. It also adds free-run and rec-run timecode support.

The camera is also considerably better in low light than the Mark II (which was itself a pretty good performer in low light), by about two stops.

There are two card slots (for SD and Compact Flash cards) and users can record to both cards simultaneously, or automatically switch from one to the other when the first card is full. Instead of the 4GB limit per recording (which amounted to about 12 minutes on the Mark II), the Mark III can record up to 29 minutes 59 seconds without pause, as the camera seamlessly connects the 4GB files.

The magnesium body is apparently more weatherproof and durable than the Mark II. It also has a better LCD, using the 3.2-inch 1.04million-dot screen from the 1D X.

One problem with the Mark II that wasn’t addressed was the HDMI output, which still doesn’t produce a clean signal, so can’t be recorded on an external recorder, although the Mark III no longer reduces the resolution to 480p via HDMI when recording starts (which will be better for anyone using an add-on monitor).

Canon now faces a lot more competition than it did in November 2008. The Nikon D800, which should start shipping before April, is the obvious full-frame, full-HD rival, and it will allow a clean HDMI feed for external recording – although not the adjustable audio levels, frame rates above 30fps or higher bitrate in-camera recording of the Mark III (the D800 is limited to 24Mbps).

Canon’s own EOS C300 is a much lauded large-sensor (APS-C/Super 35mm size) video camera, which looks good in low light. And there are now a wide range of large-sensor video cameras that are relatively inexpensive (at least by the standards of a few years ago), from Arri’s Alexa to Sony’s F65, F3 and FS100, and Panasonic’s AF101. At the lowest budget end, Panasonic’s GH2 DSLR can produce lovely-looking video (once it has been loaded with the independent Driftwood hack that allows it record at up to 176Mbps).

At the C300 launch, Canon also promised to introduce a new 4K Cinema EOS full-frame DSLR camera by the end of this year, which may be a further consideration.

“The EOS 5D Mark III represents a big step forward for the EOS 5D series,” said Kieran Magee, Marketing Director, Professional Imaging, Canon Europe.

It “is an exceptional camera and we’ve listened carefully to feedback from its passionate community of users to improve performance in every area. This camera has been designed to meet virtually any creative challenge – it’s faster, more responsive and features the tools to adapt to everything from studio photography to creative videography, while producing results of the highest quality,” he claimed.

The EOS 5D Mark III will be available from end of March 2012, with a list price of £3,000 / €3,570 including VAT, or $3,500.

By David Fox

Gekko lenslite DSLR mount

Gekko Technology will introduce a new DSLR mount for its established lenslite at IBC. The mount will allow direct attachment of the colour-stable, robust ringlight to Canon 5D, 7D and Nikon D3 cameras.

It will fix directly to the base of the camera via the tripod screw and secures 15mm bars that hold the lamp head on axis around the lens. The base of the mount has an additional fixing so the camera/lenslite combination can still be mounted on a tripod, but with the centre of gravity moved forward for stability.

“DSLR cameras such as the Canon 5D have become very popular tools for video content acquisition and look likely to remain so given their versatility,” commented Gekko founder and MD, David Amphlett. “The new lenslite DSLR mount provides all the benefits of a high-quality solid-state fixture that was once only the domain of much larger professional cameras."

Designed for studio or location production, and with a colour temperature of 5600K, lenslite delivers 260 foot candles of intensity at a distance of 1m. It can be used as a primary light source or as soft fill, and powered by any 12-volt to 40v power source. Accessories include filter stages, gel holder, gel cutting template, adjustable French flag, wireless or cabled dimmers and a remote DMX interface.

By David Fox

Lensbaby Tilt Transformer

Panasonic AF100/AF101 and Sony Handycam NEX-VG10E users who want to create a tilt/shift effect with their cameras will be able to fit a new Lensbaby Composer with Tilt Transformer, which will allow them to mount any Nikon lens and tilt up to twice the amount of standard tilt-shift lenses.

The adaptor will initially fit any Panasonic or Olympus digital camera using a Micro Four Thirds mount (such as the upcoming AF100/AF101) and will also come in a version later in the year for alpha-mount cameras such as Sony's NEX range, priced at $250 and $350 respectively.

The Tilt Transformer allows users to capture pictures that have a slice of focus through the image, bordered by a soft blur. Lensbaby already makes relatively inexpensive, lower-quality Optic Swap lenses allowing interesting tilt/shift type effects, but the ability to fit a higher quality lens make them even more interesting. It gives 12.5º of tilt in any direction.

“We got excited when we realized that the Lensbaby Optic Swap system could be extended to include Nikon mount camera lenses, including primes, fisheyes, zooms and macro lenses," said Craig Strong, Lensbaby Co-Founder and President.

Tilting a Nikon mount lens on the Tilt Transformer will place the slice of focus in different orientations within the image. Vertical, horizontal, and diagonal slices are possible depending on the direction the lens is tilted. Objects in both the foreground and background can be in focus within that slice. For example, a user can focus on one person close up in the left portion of the frame while also focusing on someone standing much further away from the camera on the right side of the frame. The ability to focus on several items at once (while blurring out the rest of the image) when each item is placed at a different distance from the camera, is typically possible only with traditional tilt-shift lenses or view cameras. It can also be achieved in post, but that is easier for a single frame than for a video clip.

The size of the slice of focus is dependent upon the aperture used. For example, f/1.4 will produce a very thin slice of focus with abundant blur. F/22 will produce a very wide slice of focus with just at tiny bit of blur. Also, when tilting extremely and shooting at a very wide open aperture like f/1.4 the slice of focus will appear even thinner than when shooting at f/1.4 with minimal tilt.

There is also a built-in mechanism that allows Nikon G lenses to function properly at all apertures. Nikon G lenses do not have an aperture ring on the lens itself. This mechanism allows the aperture to open and close by manually rotating the lens.

The Tilt Transformer is also compatible with the Lensbaby Optic Swap System and ships with a Double Glass Optic installed, while other optics can be swapped in and out, for different effects (such as Pinhole or Soft Focus). The Lensbaby optics typically give a round, gradient blur effect rather than the slice of focus you'd get by adding the Nikon lens.

There's a good review of the Tilt Transformer on DP Review's Micro Four Thirds forum (with photos).

By David Fox

Nikon D7000 full HD DSLR launched

Nikon D7000 Launch from UrbanFox.TV on Vimeo.

Nikon's new D7000 is not, as some rumours had it, a replacement for its D90, but will sit in the Nikon range above the D90 and below the D300s.

It is Nikon's second full HD DSLR, following the recently introduced D3100, but has a lot more to offer than the entry-level model.

In our brief tests of a pre-production model, there seemed to be a fair bit of noise from the auto-focus motor. At 1600 ISO, there was noticeable grain, but it wasn't objectionable – although a JPEG taken at the same setting exhibited less grain. As you'd expect with a CMOS sensor, there was skew caused by the rolling shutter, but this seemed to be less than was evident on the D3100, and barely noticeable at any sensible panning speed (and got lost in motion blur if panned much faster).

We shot several videos (which we can't show because it wasn't a production model), but the bit rates on these varied from 23.96Mbps to 27.82Mbps – a higher rate than on the D3100 (which averaged about 20Mbps), however, these were shot indoors, in an artificially lit room in fairly poor light (at ISO 1600), which would probably push the compression a bit higher than the better lit conditions we tried the D3100 out in. That said, the picture quality was good, with accurate colour rendition.

Price (list):
£1099.99 / €1303 (Body only) or
£1299.99 / €1540 (D7000 + 18-105mm VR kit lens bundle)
It should start shipping 29th October 2010.

Features include:

• 1920x1080 @ 24 frames per second, 1280x720 @ 24, 25 and 30 frames per second;
• MPEG4 AVC/H.264 compression using  .mov file format;
• Stereo microphone mini jack input - recording 16-bit PCM audio at 48kHz;
• 3-inch TFT LCD Monitor, with 921k-dot resolution;
• Video clip trimming;
• Mini HDMI output;
• Simple, direct access, Live View and video recording control;
• Tone and colour controls that let you set the look and mood of your pictures and movies before you shoot;
• Good low-light performance (100-6400 ISO, extendable up to 25600 ISO);
• Twin SD memory card slots (SDHC and SDXC) allow for extra storage capacity;
• Bundled ViewNX 2 software, easy-to-use Windows software for editing photos and movies;
• New image-processing engine, EXPEED 2, which delivers higher image quality and faster processing;
• New 16.2 megapixel CMOS image sensor; 
• Rugged, magnesium top and back with dust and moisture sealing;
• Glass Pentaprism Viewfinder with 100% frame coverage and 0.94x magnification;
• Newly developed AF system featuring 39 focus points, including 9 cross-type sensors in the centre;
• AF-F during video recording, giving continuous focus;
• Face detection with contrast AF that is claimed to be is faster than previously;
• The ability to detect up to 35 faces within about 0.08 seconds, even if subjects are not directly looking at the camera;
• Subject Tracking to keep moving subjects in focus;
• New 2,016 pixel RGB metering sensor

Weight: 780g including battery.

Magnesium top and back

Level indicator

www.nikon.co.uk

[UPDATE: Nikon has posted a firmware update for the D7000 that reduces occasional video problems where shots of dark scenes or objects might exhibit bright spots]

Related posts: Nikon D3100 full HD DSLR + Nikon D3100 video interview

By David Fox

Beating budget bugbears and bitrates

There is a lot of really great technology being used on budget cameras – unfortunately, not all on the same camera…

Whether you are using an HD DSLR or any of the many compact camcorders, it is possible to produce very nice looking pictures. It isn’t easy and broadcasters might flinch from the results because some aspect of your camera doesn't meet their technical requirements for HD. However, the distance between the camera you have and the camera you need seems bridgeable. So, why isn't it being bridged?

At the HD Masters 2008 conference, Andy Quested, principal technologist, BBC HD, stated that he essentially wanted a camcorder with the front end of a Sony EX1 and the back-end of a Panasonic HVX 200 (or similar), as the BBC didn't believe that compact cameras with sensors of less than half an inch or inter-frame camera compression below 50Mbps were good enough for HD. Given that as the BBC goes, many others would follow, you'd think manufacturers would have rushed to produce something with exactly those specifications.

After all, there are an awful lot of Sony Z1 HDV camcorders out there (which were used to shoot observational documentaries and more in standard definition), and production companies are crying out for an HD replacement.

For that market, size is critical, as is ease of use. Price is also an issue, but less critical than you might think if the technology is right. However, manufacturers would prefer that broadcast users would buy their larger, more expensive models, which are not what productions need.

At the moment, the closest to the ideal seems to be the new Canon XF300 and XF305 camcorders, which are the most affordable cameras on the BBC's latest list of approved cameras for HD production – although they are only permitted for use by independent productions. The XF300 costs less than £6,000, while the XF305 (pictured) adds HD-SDI output, Genlock input and Time code i/o for about 10% extra. The other cameras on the approved list cost at least three or four times more.

The XF models are Canon's first Full HD MPEG-2 4:2:2 50Mbps camcorders (meeting one of Quested's parameters). They record MXF files to Compact Flash cards, and are highly compatible with broadcast post production. Most rival cameras record 4:2:0.

However, behind their 18x L-series HD lenses, the cameras have three 1/3-inch CMOS sensors. Although they are claimed to offer "exceptional colour accuracy, wide dynamic range and low noise" and use high-speed data readout (2x speed) to minimise the rolling shutter skew common to most CMOS camcorders, the sensor size isn't ideal.

The cameras also offer slow and fast motion recording, with 20 speeds to choose from in 720p mode and nine in 1080p (normal recording speeds are 1080 50i or 25p, 720 50/25p (in the European versions). The upcoming Canon XF100 and XF105 use the same recording system, but have only one CMOS sensor, which will inevitably diminish picture quality - even if that won't be evident to many viewers. However, their size seems perfect for typical self shooters.

Sensor sensibility

What many productions would like are larger sensors. Much larger. Conventional broadcast cameras tend to use three 2/3-inch sensors, but HD DSLRs usually use a single APS-C sensor (some 5.5 times larger and roughly the size of a 35mm movie frame). This gives very shallow depth of field and permits the use of a wide range of excellent lenses that are often relatively inexpensive (by video standards). Some DSLRs, such as the Canon EOS 7D, can also be fitted with PL-mount cine lenses.

The results can be excellent. However, there are lots of compromises to be made. The latest slew of HD DSLRs from Sony, Nikon and Canon suffer from a range of "features" that can frustrate anyone trying to use them for serious video production.

The recording bitrate on HD DLSRs and budget camcorders is almost invariably too low. The Canon 550D/60D/7D trio are about the best of the bunch, recording at 44Mbps, but Sony's DSLRs record using the more efficient AVCHD, but at just 17Mbps (despite the fact that the AVCHD standard goes up to 24Mbps). Nikon hasn't revealed official figures for its new D3100, but our testing showed about 20Mbps on a pre-production model. At the very least both should have aimed for 24Mbps.

Panasonic's micro-four thirds cameras are similarly constrained – despite the fact that its consumer camcorder division makes a little three CMOS camcorder, the SD700, that records AVCHD at 28Mbps (at 50/60p).

Both Panasonic and Sony also seem to have settled on AVCHD at 24Mbps for their compact professional camcorders, such as Sony's NXCAM or its upcoming DSLR-based Handycam NEX-VG10E (pictured). When Panasonic first showed a mock-up of its forthcoming 3D camcorder it had an AVC-Ultra logo (which would have meant recording up to 200Mbps), although AVC-Intra (at 100Mbps) would have been more than acceptable. Instead, the AG-3DA1 records 24Mbps AVCHD when even its consumer Mini-Me version (the new SD700-based HDC-SDT750) records at 28Mbps…

Bitrate hacked

The improvement a higher bitrate can make is easily seen on Panasonic's GH1 camera. It has been hacked to record at higher bitrates.

Andrew Reid of eoshd.com shot a test on the GH1 at ISO 1600 using both 1080/24p AVCHD at 44Mbps and 720/30p MJPEG at 70Mbps – both show a considerable improvement over the standard 17Mbps, although the AVCHD is a clear winner.

EOSHD GH1 High Bitrate Test - Low Light from Andrew Reid

Of course, HD DSLRs have other hurdles to overcome, not least aliasing and moiré patterns, which are evident on Reid's video. Panasonic promises to address this problem with the new AG-AF100 / AG-AF101 camcorder, which is based on the Micro Four Thirds sensor and lens system used by the GH1. However, the AG-AF101 is also limited to AVCHD 24Mbps 4:2:0. It also appears that Panasonic may have taken action to prevent the hack working on the most recent shipments of the GH1, so the AF101 may not be hackable either. Perhaps Panasonic should offer its own 44Mbps (or higher) version at a reasonable mark up.

The NEX-VG10E and AG-AF101 are just the first of several DSLR-inspired cameras coming over the next few months, and hopefully will inspire the likes of Nikon and Canon to respond with more video-friendly features, such as peaking and zebras to aid focusing and exposure, anti-aliasing, better audio controls, those higher bitrates or, at least, HDMI interfaces that allow non-compressed video to be recorded in a nanoFlash or similar higher bitrate recorder. CMOS sensors with less pronounced rolling shutter defects would be nice too.

Despite the problems, the artistic possibilities of HD DSLRs and their ilk can make all the hassle worthwhile. Canon's 5D Mark II, with its even larger full-frame 35mm sensor, was used to shoot the finale of last season's run of House. It had a noticeably different look to the standard film production, but worked well for what they wanted it to do. For the upcoming season of House the 5D will be used routinely on episodes, especially when they want a more intimate look. This certainly proves that the rapid adoption of HD DSLRs has not just been for cost reasons. It certainly hasn't been for ease of use….

By David Fox

Nikon D3100 video interview

Nikon D3100 HD DSLR launched from UrbanFox.TV on Vimeo.
 
We did an interview with Nikon UK's Enthusiast Product Manager, Simon Iddon, about the new Nikon D3100 HD DSLR, which is due to start shipping in September.

Related post: Nikon D3100 full HD DSLR

Nikon D3100 full HD DSLR

Nikon was the first DSLR camera manufacturer to offer a stills camera that recorded HD. When its D90 was introduced in September 2008 it was 720p. Only now has it developed a DSLR that shoots full 1920x1080 HD – however, its new D3100 model only shoots 24p. This may leave some unhappy, particularly in Europe where 25p works perfectly with our video standard. However, the camera offers other much-requested features that make it worth a look.

The D3100 is Nikon's replacement for Europe's best selling DSLR, the D3000, and with a list price of £500 (body only) or £580 (with 18-55mm kit lens), it will undercut Canon's entry-level 550D.

It should be easier to shoot video on than its Canon rivals, as it has auto-focus while recording, which seemed very quiet when we used it on a pre-production model. It also has face detection and auto tracking, so that it can follow a face in a shot and keep it in focus. It draws a box around the face, or faces it has selected (it can prioritise up to 35 faces - so long as they are looking in your general direction), trying to select the best focus settings to suit as many as possible. As DSLR lenses typically have narrow focus wheels with limited travel, having to focus manually while recording usually lacks precision, which is why add-on focus wheels or follow-focus systems are recommended for any serious work, so auto focus that works as well as this seems to is a great feature.

It also records MPEG-4 AVC/H.264 .mov files, instead of Motion JPEG AVI files, which should make it more edit friendly – it comes with video editing software and users can do simple trimming in the camera. It only records mono audio, but any serious HD DSLR user will use a separate audio recorder anyway (we use the Zoom H4n). We recorded several brief tests (which we can't show as it wasn't a production model) that indicated a variable bit rate around 20Mbps (compared to up to about 44Mbps for the Canons) – as Nikon couldn't give us an official figure this may change. It also exhibited rolling shutter defects (skewed verticals during panning), as you'd expect of a CMOS sensor.

With the replacement for the D90 expected soon (there is rumoured to be an announcement in September), it may be that Nikon is leaving higher-frame rate (and hopefully higher bitrate) recording for its more professional model, which should also benefit from auto-focus, making it a better competitor for Canon's HD DSLRs.

D3100 specifications

The D3100 has a new 14.2 megapixel CMOS sensor (the D3000 used a 10MP CCD), which is APS-C sized, although marginally bigger at 23.1x15.4mm than the 22.3x14.9mm APS-C sensor used in the Canon EOS 7D and 550D (Rebel T2i).

Other features include: HDMI output; "great low-light performance" (ISO 100-3200 with a boost to the equivalent of 12800); a more powerful Expeed 2 digital signal processor (1.5 times faster than the D90) for higher picture quality and greater efficiency; and 1280x720 recording at 24, 25 and 30 frames per second. It is also small, light, and has improved ergonomics. We found it good to handle, with all the main controls easily accessible.

Nikon also announced four new lenses with built-in vibration reduction: a DX 55-300mm f/4.5-5.6G ED VR (for APS-C cameras), plus three full frame 35mm lenses: 28-300mm f/3.5-5.6G ED VR; 24-120mm f/4G ED VR; and 85mm f/1.4G – a replacement for one of its most renowned lenses.

[UPDATE: DP Review has a comprehensive review of the D3100]

See the Nikon D3100 promotional video below.


At the press launch in London they had shot another video in Covent Garden that looked a lot more colourful than this Colorful Moments video (below) which looks rather washed out (over exposed) to me, but today's video doesn't seem to be available online (probably due to music rights).


Related posts: Canon cuts cost of HD and HD DSLRs: nice pictures, nicer price and Nikon D3100 video interview

By David Fox

New lens options for budget camcorders

Many people who buy camcorders with interchangeable lenses only have one lens - mainly because video lenses can be as expensive as the camera itself. Now a small British company, Adaptimax, has brought out a range of adapters that allow you to fit stills photography lenses from Canon and Nikon to 1/3-inch or half-inch camcorders, such as Sony's PMW-EX3, HVR-Z7 or HVR-S270, JVC's GY-HM700, GY-HD 100 or 200, and Panasonic's HPX300. The Canon converter only works with Canon EF lenses and the EX3.

It previously had an EX3 adapter for Nikon lenses, but only old lenses that had an external aperture ring (a limitation that also applies to its new 1/3-inch bayonet adaptor). However, its new Adaptimax Plus (for the EX3 - pictured right) can use all Nikon lenses, including DX and G-series models, and allows users to open and close the aperture using a thumb screw.

It opens up a whole array of interesting lenses to camcorder users (a Nikon 55mm macro lens can be bought for as little as £50 on e-bay - one is pictured top fitted to the Z7). "You can also add very long lenses. When you factor in the crop factor of an EX3 (5.4), a 1000mm lens becomes 5400mm," explains Steve Shovlar, Adaptimax' sales director. "You don't lose any light, so you can stop right down." Prices range from £195 to £235.

By David Fox

HD DSLRs: nice pictures, nicer price

One of the most exciting developments of the past year, for those whose ambition is larger than their budget, has been the introduction of HD DSLR cameras, most notably from Canon. These allow the use of lots of relatively cheap, high-quality lenses with an APS-C (about 23x15mm) or even 35mm (36x24mm) sensor that can capture beautiful images for less than the price of a Sony EX1 or other low-budget professional camcorder. The APS-C sensor has about 5.5 times the area of a 2/3-inch sensor used in most mainstream broadcast cameras (and about ten times the area of a half-inch sensor used in the EX1 - although broadcast cameras usually have three such chips so performance isn't exactly comparable).

As HD DSLRs are designed primarily for stills photography, they don't have the ergonomic layout you'd expect from a video camera, and there are limitations in what controls you can use while recording and in facilities (especially audio). The choice of recording codecs is not always ideal either. But low-light performance is often excellent, and they are particularly useful for stop-frame animation or time-lapse videos.

Virtually all CMOS sensors used on DSLRs (as with most low-end camcorders) exhibit rolling shutter artefacts (when the camera is panned any vertical lines in the picture will wobble while photographic flashes may only occupy part of the picture). High-end digital cinema camcorders typically use a global shutter (which electronically shutters all pixels simultaneously) or simply readout fast enough from top to bottom to reduce or avoid it. However, it is certainly a problem with the current crop of HD DSLRs, necessitating slower panning speeds, the use of Steadicams or shake reduction technology for hand-held shots, or fixing the problem in post, with the likes of The Foundry's RollingShutter plug-in for Nuke and After Effects (watch a video about RollingShutter).

A further issue is audio. Many of the higher-end cameras have a mini-jack input for mono or stereo audio, some rely on inadequate built-in mics. However, it is generally best to work with them like a film camera and record audio separately.

There are also restrictions on the length of clips that can be recorded at one time (12 minutes on the Canon EOS 7D, for example), possibly to avoid sensor heating or power problems, and users have to be careful to buy memory cards that are fast enough that they will record all the way through without problems (there can be a big difference between card manufacturers on this, with some performing better at a lower stated class than others do at a higher classification).

If you're wondering what difference would it make buying a 35mm sensor over an APS-C or broadcast 2/3-inch sensor camera: 35mm will give you shallower depth of field (less of the picture in sharp focus - and more of it, especially the background, pleasingly blurred). However it can also be a nuisance. You can set up a shot, have the subject perfectly in focus, start shooting and he's moved back or forward slightly and is now out of focus. In most situations, you'll be able to get as little depth of field as you'll ever need with an APS-C sensor (and often even with 2/3-inch chips). Of course, the larger the sensor, the better quality image you should get - especially in low light, as the pixels aren't as closely packed together (but a 25megapixel 35mm sensor will have about the same pixel density as a 10 or 11MP APS-C sensor), and you're only going to be shooting at 1 or 2MP for HD video - so how the recording codec performs may have a bigger impact on your video quality than the sensor size.

Playing the field

The camera that started this trend is Canon's EOS 5D Mark II (the first 35mm HD DSLR - pictured top in use with a Vocas DSLR rig), which is ideal for anyone who wants shallow depth of field at the lowest price possible.

It currently records 1920x1080 at 30 frames per second (which has been a problem for those of us in Europe, although that can be dealt with – look at filmmaker Philip Bloom's website for suggestions). However, that will be rectified early in 2010 when Canon promises to update its firmware to allow 24 and 25fps. It has already updated the camera to allow full manual exposure while recording video.

[UPDATED: The 24/25fps update (firmware 2.04) is now out and also adds full manual audio controls.]

The new Canon 1D Mark IV already has full HD at 24, 25 and 30fps (plus 720p/50 and 60), but uses a slightly smaller 1.3x crop sensor (APS-H - although its performance in low light seems to be particularly good). The recently introduced Canon EOS 7D offers the same formats on a less expensive APS-C model (about 1.5x crop). Files are saved using AVC/H.264 compression in a .MOV container (at about 44Mbps for full HD), with Linear PCM 48KHz audio.

[UPDATED: There is also now the Canon EOS 550D (Rebel T2i in the US), which is smaller and lighter (and about half the price for the body) than the 7D, but offers the same video formats on the same sensor - although it isn't as feature rich as a stills camera as the 7D.]

Although Canon is the key manufacturer of HD DSLRs, others have entered the market.

The APS-C Nikon D90 was the first DSLR to record HD video, at 720p/24, as now do Nikon's 35mm D3S and APS-C D300S and D5000 models, using AVI Motion-JPEG codecs.

The compact Pentax K7 is another APS-C 720p camera, but only at 30fps (AVI Motion JPEG at about 45Mbps variable), although it can also shoot at a non-standard higher resolution (1536x1024 - 3:2 aspect), however the even smaller Pentax K-x records 720p at 24fps, has very good low-light performance, and is currently about the cheapest HD DSLR available. Both Pentax models benefit from in-body shake reduction, which means that they can be used hand held with inexpensive, old prime lenses.

The Panasonic Lumix DMC-GH1 has an interchangeable mirrorless lens system, which means it can be smaller than conventional DSLRs, although it also has a smaller (Micro Four Thirds) sensor with a 35mm crop factor of about two. It seems to be the only "HD DSLR"* that can auto-focus while recording video, although that should be less important for anyone coming from a video or film background than it seems to be for stills photographers moving up (although autofocus only works with certain lenses). It records 1920x1080 at 50/60i or 24/25p using AVCHD (about 17Mbps), or can record 720p/50 AVCHD or 720p/25 using Motion JPEG (.MOV at about 28-30Mbps). Tests show a lot more artefacts in 1080 than with 720, which isn't surprising as the bitrates are the same. There is also the cheaper Panasonic GF1 which only records 720p/60 and 30.

*Note: Of course the Panasonic isn't a DSLR - as it doesn't have a mirror (the Reflex), but as it has interchangeable lenses it should probably be included here....

Related Posts: Cheap 35mm video - Canon cuts cost of HD - HD DSLRs: Still developing

By David Fox