Clearly High-Definiton?

Crunchgear - When HD is not High-Definition

by Devin Coldewey on May 18, 2010

Remember the “megapixel myth” that has driven camera specs for the last decade or so? Yeah, it’s still here; it’s called the “HD hoax” now. I just made that up. But seriously. The idea behind the megapixel myth was that simply increasing the size of the output image didn’t usually result in a better picture in any way. In fact, in addition to filling up the memory card faster, this megapixel bloat led to images that were noticeably less sharp and true to life. Similarly, so-called HD cameras and sensors are now being sold strictly on numbers and not on features or performance. But more data for the image is always better, right? Not quite.

What set this post off was that yesterday, Omnivision announced that they were packing 1080p onto a 1/6″ sensor. An admirable feat of miniaturization. But the reality is that this “high definition” is anything but.

Now, every camera that I’ve shot with, including the impressive T2i, has problems with HD. Somewhere along the line, in one of those steps I mentioned above, something goes wrong. And with imaging, it only takes one weak link to create a bad photo or video. High definition shouldn’t just be a name for a resolution. It should mean the level of definition in the image is high.

The pocket cams out there, for instance, can barely ape “HD.” Under the correct circumstances, in good lighting and with no motion, you would look at the 720p image and think “yes, that’s high definition.” For the most part, though, motion is blurry, colors are mixed, edges are indistinct, and there’s a weird sort of texture over the whole frame. What the hell? You paid good money for “full HD” (as the pocket cams are now advertising: 1080p in a phone-sized package). Why aren’t you getting images like the ones you see on TV?

How can you avoid this? Well, just like the megapixel race, you really can’t. Video recording devices are simply going to overdo it the way still cameras overdid it, and now we all have hundreds or thousands of dubious images which despite being 10 or 15 megapixels, if you look closely or print too big, have all kinds of weird artifacts in them. It’ll be the same for video. You can choose to record at a lower resolution; 720p (even VGA sometimes) is just fine, after all, and often will record at the same framerate, meaning better image quality. And actually look at the lenses on the cameras you buy. Lenses that are bigger across are (generally speaking) better, and every lens has its F numbers printed on it or in its spec sheet. If you’re trying to decide between a few cameras, look at their lenses: if one device maker is shirking on the lens, arguably the most important part of the camera, then you can be sure they shirked elsewhere too. Also, don’t buy anything that shoots in 1080i. Interlacing is a monster deserving of its own post.

I’d like to say that my issue with inflated video resolutions (and megapixels) is something that will be alleviated by time, like some of Ebert’s objections to 3D. But the cost of good optics isn’t really coming down, and really, the size of the lens is a physical barrier not likely to be surmounted any time soon. The methods we have for collecting and measuring light aren’t sufficient, and the improvements yet to be made for them will do nothing to help the fact that with bad components, it’s garbage in, garbage out.