UPDATE: James Miller removes optical low-pass filter from 5D Mark III for resolution increase / new footage

Update: James has had a full day’s shooting now with the modified 5D Mark III. Check out the footage above.

Warning: please wait for this to all shake out. Don’t hastily modify your 5D Mark III without the necessary technical knowledge and research. Opening the camera voids the warranty and risks irreparable damage.

James Miller has decided to open up his brand new Canon 5D Mark III, tear it down and remove the blurring anti-aliasing filter from in front of the sensor. It does seem like a particularly strong optical low pass filter on this camera, which produces very soft results in video mode.

5D Mark III - anti-aliasing filter removed

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Frame grab – 1080p, OLPF present
Frame grab – 1080p, OLPF removed

Canon’s 3×3 binning has been shown mathematically to produce a sharper image than the end result we get. Removing the anti-aliasing filter does help resolution but it risks introducing moire and aliasing. The frame grabs from James do seem to have worse aliasing but there’s no sign of moire. He’s shooting now with the modded camera so as more news comes along, and the first footage we’ll know more about how the OLPF-free 5D Mark III performs.

Here’s a side by side comparison (at 100% view) with / without optical low pass filter…

5D Mark III with / without AA filter

Although these were shot on different days, the same settings were used in-camera. There’s a considerable increase in detail without the filter and just a little bit more aliasing. It is a pretty nifty result.

OLPF, AA, anti-aliasing filter, call it what you will – it seems Canon put too strong a one in the 5D Mark III! Yes it crushes moire but the trade off is less resolution not just in video mode, but also for stills.

James says he needs to replace the filter glass with a clear piece of filter to prevent back-focus issues from rearing their head. It will be interesting to see how this progresses.

UPDATE – here are some shots from the teardown. Amazing how little space there is between the shutter and the back of the camera.

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