The medical photographer’s ultimate tool?
January 2, 2009 § 2 Comments
There’s been quite a lot of buzz surrounding the release of the new Canon 5D Mark II digital SLR camera (MkII). With 21.1 megapixels and a full 35 mm size frame CMOS sensor, the camera is a powerful SLR. But it’s the possibility to record HD video that is the groundbreaking feature of this camera.
Is the MkII the ultimate tool for the medical photographer?
I received my MkII just before Christmas and have been testing it during the holidays. The camera records progressive full High Definition video (1920×1080) at 30 fps. The file format is Quicktime with H.264 compression at 38.6 Mbits/sec.
Video recording is made possible as the camera’s mirror is flipped up, making the sensor register the image in “Live View” mode. The live image is then visible on the camera’s 3″ LCD, just as in compact digital cameras. As the mirror is flipped up, the viewfinder is disabled while in this mode. While watching the image on the LCD you can turn on video recording or take still photos. You can even take stills while recording video. And you have all the technical and creative possibilities of high quality lenses at your hand. There are however, quite a few downsides to this crossover camera. The main problems being the lack of manual controls and the video compression.
In “Live View” mode only focus can be adjusted manually. The camera chooses both ISO, shutter speed and aperture for you (in that order). You can lock the values so they don’t change during the shot, but you can not set them manually. For professional video this is a big problem. Not being able to adjust the aperture for example, gives you little control over the depth of field.
H.264 is a video compression standard developed for delivering video. Because of the way the data is organized it’s not a good format for editing and processing video in a production suite. A professional video camera records much less compressed video, and compressed in such a way as to keep as much of the information in each frame as possible.
But do these issues make the video component useless? Maybe for the cinematographer, but in my opinion not for the medical photographer. These are some of the conclusions I’ve made after testing the camera for two weeks:
- It does not take a lot of time to learn how to tweak the automatic settings to approximate your needs (e.g. pointing the camera at a bright light to make it decrease the ISO and then locking the setting), but it’s hard to get the exact settings you want.
- The camera can produce good video at lower light conditions than any other video camera I’ve used.
- The built-in microphone is crap and picks up even the slightest handling of the camera. Only suitable for recording reference sound.
- It’s very hard to adjust video focus on SLR lenses, and the autofocus is slow and useless.
- The video files are too big to be played back on most normal computers (I’ve tried several). So even though they’re not very suited for editing, you will need an editing system to process the files for viewing by others (e.g. down-converting to DVD).
The MkII will be my new still photo workhorse, but it’ll definitely not replace any of my video cameras. It’s a step in a very exiting direction, though. The crossover between still and video photography has just begun and who knows what the next generations of SLR cameras will be able to do.
For the medical photographer most used to still photography the MkII can offer a way to start learning to work with video. It can also be an easy way to record supplemental live documentation of a patient without having to bring a video camera. I’m also quite exited to test filming video through an extreme macro lens. As for surgery, I’m looking forward to see how the camera handles all the different shades of red and the extreme contrasts of the OR.
I’ll post on that later, when I’ve tested it in a clinical setting.