Canon EOS 5D Mk III & 1D X “Highlight Tone Priority” Aperture Problem and Solution
Thomas Boyd, who of course posts regularly on here, recently brought this to my attention for the Canon EOS 5D Mk III, and then Bob Davis, friend and exceptional photographer, raised the same issue with the new Canon EOS 1D X. We’ve been doing some testing, and have solutions and work-arounds for both existing and future photos made with these cameras.
Photos shot on the Canon 5D Mk III and Canon EOS 1D X that are properly exposed, and look great in the JPEG preview, Photoshop, Lightroom and Photo Mechanic, render at least one full stop darker when decoded by Aperture.
The “Highlight Tone Priority” feature in these cameras appears to be confusing Aperture’s RAW decoder.
Solution for future photos
Disable “Highlight Tone Priority” in the cameras and the RAW files render just fine.
Solution for existing photos
Import into Lightroom (download free 30-day trial version here) and export as 16-bit TIF files, then import those into Aperture.
Long Term Solution
This is an issue that needs to be addressed by Apple.
I can’t pretend to know why this is happening in the first place, except to say that by having “Highlight Tone Priority” enabled in-camera, even though the JPEG preview (or JPEG created in a RAW+JPEG shoot) looks great, as soon as you click on the RAW image in Aperture, you will see it initially looking as expected, then once the RAW file is actually decoded by Aperture, the image will darken noticeably.
The easiest solution moving forward is to simply disable the “Highlight Tone Priority” feature in the camera. Obviously this isn’t 100% ideal, as there are times when you may want this feature to be enabled, but at least there is a workable solution while we wait for Apple to fix this. And the only reason I say this is specifically an Apple issue is because neither Lightroom nor Photoshop nor Photo Mechanic exhibit this behavior.
On the other hand, you may have photos already made that are exhibiting this problem. And if you weren’t aware of the issue, or if you hadn’t compared the Aperture render to the output from another application, you may have found yourself believing that either your camera has a problem, or you do!
Here’s a clear example of the difference. The image on the left was imported into Lightroom, exported as a 16-bit TIF, and reimported into Aperture. The image on the right is the original RAW file, as decoded by Aperture. When that RAW image on the right was first imported, it initially looked just like the one on the left, but then once Aperture rendered the RAW, it darkened as you see here.
Simply increasing the exposure, or adjusting levels or curves, doesn’t fix it, either. While the overall exposure will probably become acceptable, the shadows tend to lift too much and overall, noise becomes more prevalent. Needless to say, that’s not a Good Thing™.
Apple needs to address this issue, but in the meantime, at least those of you with either of these cameras have a workable solution.
According to reader Thomas Emmerich, the Canon EOS T4i / (650D in the US) is exhibiting the same “Highlight Tone Priority” problem.
Anyone else seeing this on other cameras?
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