James Miller has posted over at Philip Bloom’s blog about a teardown he just did on his new 5D MKIII DSLR. He says he wasn’t happy with the sharpness he was getting from the camera, so he set about to remove the Optical Low Pass Filter.

An OLPF is a glass filter built into all video cameras that helps limit super-fine detail from reaching the sensor, which can result in moire artifacts. All camera sensors have to deal with moire, it’s not something that is unique to DSLRs. However, when a DSLR improperly downscales video from it’s high-resolution sensor to 1080p, moire artifacts can appear worse. Such is the case with the DSLR video camera that really started it all, the 5D MKII. The MK2 skips lines when downrezzing to 1080p, and that quick-and-dirty downscale technique, along with the lack of a video OLPF, makes the camera a moire-machine. In fact, there is a company that built an aftermarket OLPF specifically for the 5D MKII, the VAF-5D2. This is a good bandaid solution, but it vignettes on some wide lenses, and you can’t shoot stills with the OLPF installed. The solution is a proper OLPF built into the camera, which is exactly what the 5D MKIII offers. Unless you remove the filter in an attempt to gain more sharpness.

James removed one of the two OLPF filters in his Mark 3, and seems happy with the initial results. I have to say that from the examples I’ve seen, it looks like a marginal improvement at best. And for that, you’ll have to invalidate your DSLR warranty by taking it apart…the OLPF is attached to the sensor block, so everything must come out to get at it. Assuming you don’t break anything, there’s also a major risk of mis-aligning the sensor when you put the thing back together, which can lead to all sorts of focus/image plane issues. I’d file this one under the “interesting, but don’t try this at home” category. If you really want this mod, there is a company that can do it for you.