It appears that our friends the Canon EOS 5D Mark II, Canon EOS 7D, and the Canon EOS-1D MKIV have some aliasing issues when shooting video. We've seen some discussions about it in the past and we haven't experienced it ourselves, but it appears to be something you should be aware of before you go out to make the most epic video ever. Stu Maschwitz over at the ProLost blog has posted a very informative article on aliasing that you really must read.
Here's a snippet or two:
“The article by Barry Green is about the oft-reported â€œaliasingâ€ artifacts in video from the Canon HDSLRs (5D Mark II, 7D, 1D Mark IV). Barry does a great job of backing up a few steps and defining the term aliasing.
Aliasing occurs when you sample something infrequently enough that you create an impression of something that wasnâ€™t there. Imagine a blinking light in a room with a door. You must open the door to check the status of the light. If you open the door often enough, you get a pretty good picture of the status of the light, maybe something like on, on on, off off off, on on on, etc. Your samples are frequent enough to accurately represent the lightâ€™s activity.”
“The current crop of HDSLRs cheat in a big way to make video. Their sensors are not designed to blast an entire, full-resolution image out every 30th of a second. So Canonâ€™s engineers (and Nikonâ€™s and even Panasonics to some degree according to Barry) did what stills camera makers have always done with the â€œgood enoughâ€ video modes on point-and-shoot cameras; they grab something less than every photosite. They look at the blinking light less often, and as a result they can pull off a whole picture at a rate speedy enough to make video.”
Let's be cautious about blowing this all out of proportion tho – there are thousands upon thousands of movies being made with these hybrid DSLRs with no problems… and if you're aware of some of the limitations of the camera as you use it, then you'll be a lot better off. I see some of the comments posted in Stu's blog indicating that the sky is falling and video on these cameras is trash, but we all know that isn't true… so let's take this information and be better filmmakers with our cameras ok?
Please rush over to Stu's blog post to read it all!
(Photo credit: snap from stu's blog)