Field Monitors and Canon DSLRs – some facts

If you combine this:     with this:    you might be

losing up to 36.7% of your monitor’s picture resolution and not even realize it. Fortunately you can get your monitor to use most of its pixels again by following a few simple guidelines.

First off, the image sensor in Canon cameras like the 5D and T2i have an aspect ratio of 3:2. The trouble comes when you connect a 4:3 or 16:9 field monitor to the DSLR via the HDMI cable. The camera sends a 1920 x 1080i signal through HDMI but in reality what you’re actually seeing in the monitor is only 1620 x 1080, or a 3:2 aspect ratio (same as the sensor) imbedded in the 16:9 HDMI stream. In order to appear as a widescreen shape the camera will pillarbox the 3:2 image to fit the 4:3 or 16:9 monitor screen shape. Then the monitor will letterbox that frame so you can see all of it. Are you confused yet? Not to worry. And if you don’t have a DSLR you can skip to the last paragraph. It’s okay. Really.

The better field monitors on the market today will have two important features to manipulate the image coming down the HDMI cable. They are zoom and scale. Zooming into the 3:2 image to fill more of your monitor’s screen will not soften the image. On the contrary, because there are more pixels on the camera’s sensor than there are on your monitor’s screen the image will actually sharpen up because you’re giving the picture on your monitor more resolution.

My field monitor has a screen aspect ratio of 16:10 as do many other field monitors. If I have a Canon 5D attached to my monitor the picture will initially be letterboxed and pillarboxed, reducing the picture size by a large amount. By zooming in I’ll get rid of the black borders on the sides but there will still be a bit of letterboxing on the top and bottom because I’m viewing the camera’s HDMI 16:9 picture on a native 16:10 monitor. The same thing happens when I have a widescreen video camera signal on my 16:10 monitor. But you don’t want to keep zooming in until the letterboxing is gone from your monitor’s picture because now you’ve hidden the sides of the frame. You want to see all of the pixels coming from the sensor in case there’s something in the frame you don’t want, such as a mic boom, lighting stands, etc.

The other feature you want on your field monitor is called underscan, or scaling of the picture. As I’ve already said, seeing all the pixels transmitted by your camera’s sensor(s) is critical to avoid things in the frame you don’t want. If there’s the tip of a mic boom in your shot but you can’t see it in the monitor you’ll carry on with the shot and won’t know that it’s ruined until you get home and see every pixel of that shot on your computer screen. Fortunately the picture on most good monitors can be scaled. On my particular monitor I can actually move the picture around on the screen, squish or expand it until I see the edges of the camera’s actual sensors. When I see a green horizontal or vertical line I know that’s the edge of the frame. Field monitors such as the Small HD DP6 even have presets for different video and DSLR cameras, including the Canon 5D, 7D, T2i etc.

And if you think that your camera’s stock viewfinder is showing you all the picture elements (pixels) of your camera’s sensor(s), well……it isn’t. To learn more about today’s modern field monitors there’s a number of great video tutorials here.

– Don

Written by:

Don Greening is the owner and both senior editor and videographer for Reeltime Videoworks. His arts background as a classical musician and composer gives him an uncompromising eye and ear for detail that is very important in video production. Don also hones his technical skills by updating them through courses at Emily Carr Institute of Art + Design.