Canon EOS 5D MKII: The DSLR as Video Camera – Is It a Revolution or What?

By Erika Addis

Original article published by Screen Hub:
http://www.screenhub.com.au/news/shownewsarticle.asp?newsID=33806

Introduction

Late in 2008 Canon stole the march on major competitor Nikon and released the EOS 5D MKII DSLR (digital single lens reflex camera). The intended market was the journalist who needed to post stories online with both stills and moving images and sound (see post on YouTube).

The following is a distillation of a lot of posts and blogs online, and the experiences of cinematographers and filmmakers.

Canon  7d

Tech specs of the EOS 5D and 7D:

These DSLR stills cameras take 21MPixel photos (5D MKII) or 18MPixel (7D – same size as APS-C format) plus they can record HD (1920 x 1080 pixel) movie files. For anyone taking stills, these are impressive numbers, however for those in the film and video business, the arresting numbers are the sensor dimensions, the physical size of the image capture device or chip.

  • 5D sensor (full frame 35mm) – 36mm x 24mm
  • 7D sensor – 22.2mm x 14.8mm
  • RED Digital camera – 24.4mm x 13.7mm
  • Super 35mm film (movie) frame – 24.9mm x 18.7mm
  • Super 16mm – 12.35mm x 7.5mm
  • 2/3” video – 9.6mm x 5.4mm
  • 1/3” video – 5.23mm x 2.94mm

This is a realm where size does matter, and so, whilst the number of MPixels the sensor and camera system can record is important, HD is 1920 x 1080 – only 2 MPixel. Once you have that number of pixels, you have “true” HD capability. After that, the chip size significantly determines image quality and resolution, and, offers the possibility of that elusive and very desirable “cinematic look” or quality, shallow depth of field – also called “background defocus” – a phrase possibly coined by an electronics engineer.

So what’s the buzz?

Judging by the numbers of documentary filmmakers, cinematographers and photographers who turned up at AFTRS in Sydney for the recent OzDox forum on the DSLR “Revolution” and the amount of online traffic about the 5Ds and other DSLRs on Cinematographers Mailing List (CML) and elsewhere, it seems there is something going on.

Further, the fact that Dean Semler ACS ASC used them for some shots on his recent movie SECRETARIAT, about a racehorse, and television series HOUSE is now being produced on them, clearly something is going on, and it’s not only at the “smell of an oily rag” end of the production spectrum.

Strengths of the DSLR as a video camera

  • Big chip size = beautiful HD image quality with exceptionally shallow depth of field = “cinematic look” something that has not readily been possible with the prosumer video camera to date
  • Exceptional low light capability – 6,400 ISO, 12,800 ISO, even 25,600 ISO – mind you, the noise level at such high ISOs seriously compromises the image quality
  • Compact, GREAT to shoot in difficult to access spots, including places where video cameras are not permitted, as it is (just) a stills camera
  • Amazing time lapse shots
  • Interchangeable lenses, including cine lenses
  • Documentary subjects respond to the camera just like they do with other stills cameras, readily making direct eye contact with the lens in a relaxed and easy fashion
  • Very cheap for an HD video camera
  • Media – CF cards are readily available and inexpensive

Limitations of the DSLR as a video camera

  • Contrast, colour saturation, sharpness – natively the Canon 5D MKII cameras record a high contrast and quite saturated image, which tends to “snap” from being just out of focus into super crispness. So the standard settings, particularly contrast, need to be adjusted (down) to capture a more workable image. Reducing the contrast setting increases the effective dynamic range in the recorded files, some say by 2 stops. The cameras perform best in low contrast lighting environments.

  • Ergonomics – designed as a stills camera, a DSLR camera requires considerable “work-around” rigs to make it almost as functional to operate as any video camera – e.g. the weight needs to be supported by a rig reaching onto the body (when not on a tripod), the LCD viewfinder needs to be extended and protected from light, the focus controls need expansion. The cost of these rigs can easily eclipse that of the camera.

  • LCD screen legibility – like all cameras with an LCD screen as the viewfinder, seeing the image in bright light is difficult (the optical viewfinder is disabled in movie mode). A viewfinder adaptor such as the Zacuto Z finder is essential. Given that all focusing in movie mode is judged by viewing the LCD screen, screen legibility is vital. Focus is best judged by viewing the signal on a (larger) on-board monitor.

  • Aliasing – when a (digital) sampling system fails to accurately reproduce what it’s attempting to sample, instead of an accurate representation, you get an inaccurate “alias” of it. Aliasing happens when “false data” gets through and is captured as if it was actually accurate information. There is a lot of aliasing in the Canon HD movie files, but mostly it is not readily visible. However, when it is clearly visible it can make a shot unusable.

    It manifests on fine image detail, such as the parallel lines of brickwork, of corrugated iron on a roof or stripes in fabric, and what should be, say, parallel vertical lines, can appear as diverging diagonal lines in the image – completely wrong.

    The BBC has decided that aliasing and other issues are such a problem with these cameras that they will not accept material originated on them. See here for more details on aliasing.

  • “Rolling shutter” Jell-O world – because the image is “seen” by the CMOS sensor in a progressive scan (like the way a photocopier light scans an image) not entirely in one instant (like motion picture film), fast movement through the frame can result in a “Jell-O” wobble of the image (bendy propeller blades are a common demonstration of this effect – try it on your iphone sometime). There are plug-ins (AfterFX has one) that correct this.

  • Records HD in AVCHD format using the lossy H.264 codec to 4:2:0. Quite a lot of compression, and slow to edit in natively – it’s better to transcode to ProRes 4:2:2 or Avid DNX36.

  • Record time is 12 mins maximum at a time – some would say that’s not such a limitation really, it’s like a magazine of film lasting 10 minutes – but a problem for would be “Russian Ark” style filmmakers.

  • Overheating on long runs – this shows up as gradually increasing noise in the image.

  • Black levels float on long running shots (on 5D), which then need to be adjusted shot by shot in grading – an additional “invisible” expense.

  • No way to monitor audio levels being recorded, audio Auto Gain Control is savage, sound needs to be recorded double system (back to the old ways!). If slating is not employed, synchronising can be done using software such as “Pluraleyes” which analyses the signals on the camera guide track and the sound track and matches them up.

So, is it a revolution?

No, it’s inevitable evolution along a path we’ve been travelling on for some time, and we’re nowhere near the end of it yet.

As the RED Digital camera knocked 35mm film from its place as the pinnacle of motion picture imaging systems, by offering a high quality digital cinema camera at a price that persuaded thousands of people in the business they could live with the drop in image quality, so the 5D MKII has made inroads in the same way.

Making beautiful images, with a camera that many thousands more can afford, it’s definitely a democratising influence on the production of stories for the screen. As the image quality increases and it is easier to make those pictures, so the pleasure of making the images also increases. Why wouldn’t you use it?

Well, you wouldn’t use it to make an observational documentary in uncontrolled and difficult conditions which demand skillful camera work to capture powerful images to tell the story – all the normal controls of professional and prosumer video cameras are missing from the DSLR camera.

Unless, that is, the visual style of the film includes a significant proportion of out of focus material with under and over exposure and possibly extensive use of wide angle lenses to compensate for the difficulty of framing up accurately when you can’t see the image on the LCD screen.

And you wouldn’t use it for drama work without spending a significant amount fitting it out with all the necessary work-around hardware to make it operable – e.g. on-board LCD monitor, cine lenses, follow focus control, matte box and shoulder rig. And also allowing additional funds for post fix-ups of the floating black levels and varying noise floors.

You would use it in filming conditions, both drama and documentary, where there’s some control over the subject and light and time to frame up and check focus. And for getting beauty shots, such as timelapse scenes.

So, the bottom line is, the Canon 5D and 7D are great cameras and it’s fun making beautiful pictures with them. And they are being used right now on commercials, dramas and documentaries.

But wait, there’s another high quality digital camera coming your way very soon, a video camera that is, not a DSLR, and its price tag is lower again than the 5D MKII.

Big sensor + adjustable LCD screen + interchangeable lenses with matte box + less compression + correct weight distribution + sound controls with monitoring + does stills as well as HD + lower price tag – take your guess which manufacturer – Panasonic, Nikon, Sony, Canon, JVC? More on this one soon.

But, low cost doesn’t make the hardware the best choice for the job, and the hardware (still) doesn’t make great films, people do.

So keep your eye on the real prize – great characters and powerful stories, photographed with brilliant pictures made by skilled cinematographers*.

*In the sense as used by Robert Bresson.

Erika Addis

Erika Addis is a cinematographer and she doesn’t own a Canon 5D or 7D.

Erika Addis has worked in the film and television industry for over 25 years. Her work as a cinematographer and director of photography includes a broad range of documentaries, feature films and television series’. She has many awards, including AFIs, and an ACS Golden Tripod, and an MA (Hons) in Film and Television specialising in Documentary and Screen Studies from the AFTRS.

http://www.screenhub.com.au/news/shownewsarticle.asp?newsID=33806