Contour Issues: High Contrast & Snow
If you've got a Contour helmet cam, or if you've ever watched any of my helmet cam videos, like this or this, you've probably noticed that the camera is particularly inept when it comes to dealing with bright, snowy scenes. Highlight detail tends to wash out, leaving obvious and ugly blank, featureless regions of white. The question is: why?
The answer kind of struck me out of the blue (or white) one day, when it suddenly occurred to me that there is almost certainly no variable aperture in the camera. In other words, the only way the camera can adapt to changing light levels is electronically, by varying the sensitivity of its sensor. If that's the case, how would the engineers design the camera so that it could handle a wide range of brightness levels, from sunlight to dusk to dark? The answer is, they would cheat at the ends of the spectrum.
In bright sunlight, the Contour would (theoretically) be designed to operate as close to clipping as possible, so that at the other end of the spectrum, the darks wouldn't get too noisy. So, everything is fine as long as you're shooting in bright sun under normal conditions—ie, grass, trees, and people in your back yard. But what happens when you shoot snow under full sunlight? Well, in terms of EV, this is actually a full stop or more brighter than an ordinary (non-snowy) scene. And it pushes all the highlight detail right out of the camera's range.
Similarly, shooting any highly reflective material when the sun is at the right angle will result in the same phenomenon: the brightness level exceeds the camera's expected maximum. The good news, if I'm right about this, is that there is a pretty easy fix. Just put a neutral density filter in front of the lens to reduce the light entering the camera when you shoot sunny-snowy or otherwise highly reflective scenes.
And yes, I've found an aftermarket kit that allows you to do exactly this (albeit with a polarizer instead of a true ND filter). Will it save those otherwise burnt highlights on bright snowy days? We'll have to wait until next season, as I made this logical leap a little too late to test it this year. But it sure would be nice to get more usable footage out of the Contour when shooting sunny, snowy scenes, wouldn't it? Stay tuned...
Andy Lewicky is the author and creator of SierraDescents
Dan Conger July 31, 2011 at 8:17 pm
I've noticed the same thing with my GoPro. Washes out in particularly bright light.
ScottP August 1, 2011 at 3:43 am
Your theory is sound, I'm interested to see how the test will work out.
Mike February 29, 2012 at 5:44 pm
Thanks so much for figuring this out! I was getting fed up with my Contour blowing out the highlights on sunny snow shots and not being able to do anything about it with the camera settings or post-processing.
I ordered the lens kit and a neutral density and polarizing filter today.
Andy February 29, 2012 at 6:45 pm
I did get a polarizer, and I was able to verify that the 1-stop light reduction is enough to save highlight detail in snow.
That said, I was unhappy with the results. The Contour uses a very tiny sensor, and I've since learned that tiny sensors respond poorly to filters, particularly polarizers, because of diffraction.
In my testing, the addition of the polarizer came with a visible and significant sharpness hit.
Good news, of a sort, is that both Contour and GoPro have released second-generations cams that are said to do much better with highlights. I can't verify the new Contour, but I just bought a GoPro Hero2, and that camera does indeed handle snowy-sunny scenes with no loss of detail.
A full review of the Hero2 is pending, but the quick line is that I like it, and I'm selling my Contour...
Mike February 29, 2012 at 7:42 pm
Did you try it with the neutral density filter? I'd rather not have to junk the camera, but I did buy it mainly to record skiing.
Andy March 4, 2012 at 9:49 am
Mike, my testing was with the aftermarket polarizer. As far as I know, there is no pure ND filter for the Contour cams...