School’s most recent camera purchase was tested in the shortfilm “Siivooja”

Photo by Eero Alava
Story: Hannu Koivuranta
One of the latest purchases in our school is the Canon EOS 7D digital camera. It is capable of recording Full HD-video at 25 frames per second using H264-compression. The camera had been eagerly awaited by cinematography student Hannu Koivuranta, who picked the camera as his choice of weaponary for shooting “Siivooja”. The script had been under development since spring of 2010.

The camera went through basic lighting tests, shutter speed tests, motion tests and sharpness tests in order to expose potential problems before the principal photography. Tests with color correction showed that the 7D (as well as all the other DSLRs) suffer from horrendous noise generated by underexposure. Low contrast camera filters were necessary in order to lessen the ridiculous difference between highlights and shadows. The test materials are available to students of TTVO in Tapper.

The camera in our school is at the moment lacking Arri’s PL-mount in order to use motion picture lenses, but it’s under consideration for purchase. Because of this, “Siivooja” was shot using three ordinary still photography prime lenses. The lenses were Canon EF 20mm (f/2.8), Canon EF 50mm (f/1.8) and Olympus M.Zuiko 135mm (f/3.5). The latter one was fitted using an OM-adapter between the camera body and the lens. The focus rings that were supplied with the camera’s accessory set are made of plastic and it’s very doubtful that they survive winter. The same problem exists with the follow focus, the mattebox (plastic bolts) and the filter holders. The overall feeling was very plastic and class B.

The camera was purchased with a optical viewfinder, Z-Finder Pro, by Zacuto. It attaches to the LCD-screen with a handy base-plate screwed to the camera’s bottom mount. Although the viewfinder is optically very pleasing and doesn’t strain the eye we didn’t use it during the shoot. In addition to the viewfinder our school also purchased a shoulder mount rig but unfortunately the camera cannot be placed as far left as the viewfinder needs to get in order to comfortably operate the camera: one would suffer permanent neck damage. This problem was solved by adding a small SWIT-monitor to camera left and running a video signal straight to it.

One potential problem lies with the camera’s outputs: you can only monitor one signal at a time. You can choose between video out, mini-HDMI out or the LCD screen. This is only a problem when the camera operator chooses to use the LCD screen and when the signal also has to be made available elsewhere. By using the aforementioned SWIT-monitor we were able to continue the signal through with BNC-cables which made it possible to view the image from several monitors. The school also bought a HD-SWIT-monitor which accepts HDMI.

The camera case includes two memorycards: 16 gigabytes and 32 gigabytes. One 16 gigabyte card records approximately 1 hour and 40 minutes of Full HD video. The clips are restricted to 30 minutes in length because the file system allows only a maximum size of 4 gigabytes per clip.

Exporting the clips from the memory cards was a bit weird and problematic a process since we didn’t have time to install a Final Cut-plugin. Mac-computers couldn’t identify the camera as a memory card when plugged it in so we used iPhoto and Adobe Bridge to get the clips out. After the export it is recommended to use Streamclip or Compressor to change the H264-codec to Apple ProRes 422 in order to allow real-time editing. H264 can be edited, but after a while - with the expense of render time - one understands why the change is important. AVID also has its own work flows through AMA.

The principal photography went without major problems. Although the camera is small it doesn’t make it any faster to use.

 “Siivooja” was shot primarily with ISO 200 which makes the noise bearable. A few shots were taken with ISO 320. The camera’s Sharpness-slider was also set to zero since it was inaccurate in color when overexposing a few pixel sized objects. Sometimes it also created unwanted moiré.

The lighting tests done with a Sekonic light meter didn’t prove to be correct. When metering the mid-gray from a highlight of skin, the image was heavily overexposed in the camera. Same thing went for shadows. There appeared to be a constant 2-3 f-stop difference in the values.

An  extremely important factor when shooting for DSLR is the creative use of sufficient dynamics. You cannot light this format as you would light other digital formats or film. The sensor, at its worst, reminded of a 2:1-contrast mini-DV camera sensor from time to time. The lighting should be very subtle in order to avoid overexposure and underexposure which leads to horrendous noise.

One should also take into account the so called “gray exposure”. Gray exposure is a level of illumination where the object is clearly visible but due to a slight underexposure all the color information is gray. Which means there is NO color information. This area of gray exposure can very easily remain unnoticed which later on is a disaster in the color grading stage. Also, gray exposure isn’t clearly noisy which makes it harder to notice.

The sensors of DSLRs have suffered from a phenomena called “jelly” which makes the image bend in a weird way when panned very fast. The motion is jellyish and really disturbing. While doing the jelly-tests it occurred that the bigger the shutter speed, the bigger the jelly. Shutter speeds over 250 contained very rude jelly problems, which I wouldn’t recommend. With calm but determined panning this flaw (too) can be held under control.

“Siivooja” is now in post-production. The film was directed by Toni Anttila and produced by Outi Hartikainen. Editing is done by Marie Syrjälä and sound design by Philippe La Grassa. The original screenplay was written by Iiro Peltonen. The film stars actors Aleksi Holkko, Jorma Markkula and Sari Lilliestierna. The film is to be released at the end of 2010.