Apple Log vs Apple Log 2 for LUTs: Same Curve, Wider Gamut (Tested)

Apple Log 2 keeps the Apple Log curve and changes only the color gamut, from Rec.2020 to Apple Wide Gamut. That means an Apple Log LUT on Apple Log 2 footage keeps your exposure and gray balance exactly where they should be. What drifts is very saturated color: blues and violets get lighter and less saturated, and oranges get slightly darker and duller. On most real footage the difference is subtle. Our iPhone Apple Log LUTs work on both profiles.

We didn’t want to guess, so we tested it. We took the published math for both profiles, ran a standard color chart through our Apple Log looks, and measured what changes. Here’s what we found, in plain terms.

Log curve vs gamut: the two halves of a log profile

Every log profile is defined by two things, and it helps to keep them separate.

• The transfer curve (the “log” part) decides how scene brightness becomes code values in the file. It controls where middle gray sits, how highlights are compressed and how shadows are lifted. If the curve changes, a LUT built for the old curve gets the exposure and contrast wrong.
• The gamut (the color primaries) decides what red, green and blue actually mean in the file. A wider gamut can store more saturated colors. If the gamut changes, the same RGB numbers describe slightly different colors, so a LUT shifts saturated colors while leaving grays alone.

Apple’s developer documentation describes Apple Log as BT.2020 (Rec.2020) primaries with Apple’s log curve, and Apple Log 2 as Apple’s own gamut with an Apple log curve. OpenColorIO, the open-source color management library used across film and VFX software, implements Apple Log 2 from Apple’s white paper as “the same transfer function as Apple Log, but with the wider Apple Wide Gamut primaries rather than Rec.2020.” OpenColorIO 2.6 added “Apple Log 2” and “Linear Apple Wide Gamut” as built-in color spaces.

Apple Wide Gamut’s primaries sit at red 0.725, 0.301, green 0.221, 0.814 and blue 0.068, −0.076 (CIE xy), with the same D65 white as Rec.2020. It extends well past Rec.2020 in blue and a little in red. Its green corner is actually slightly less saturated than Rec.2020’s. Because the white point is shared, neutral colors mean exactly the same thing in both profiles. That’s why grays survive and saturated colors don’t.

What happens when you put an Apple Log LUT on Apple Log 2

An Apple Log LUT expects Rec.2020 color. Give it Apple Wide Gamut footage and it reads the RGB values as if they were Rec.2020. Brightness is decoded perfectly, because the curve is identical. Color is decoded slightly off, because the same numbers now mean a different color.

How we tested it: we took the reference colors of a standard 24-patch color chart and encoded them two ways, as true Apple Log (Rec.2020) and as true Apple Log 2 (Apple Wide Gamut), using the published curve and primaries. We ran both versions through every look in our Apple Log pack at three exposures (2 stops under, normal and 2 stops over), then compared the results.

What ΔE means, in plain words

ΔE (we used CIEDE2000) is a single number for how different two colors look to a human. Around 1 is about the smallest difference a trained eye can spot side by side. Low single digits are subtle, the kind you notice in an A/B comparison rather than on a single viewing. Once you get past about 5, most people will see it straight away, especially on saturated colors.

The results

• Exposure: unchanged. The gray patches, from white to black, never differed by more than 0.65 ΔE. That’s invisible. Brightness and contrast land exactly where the look intends.
• Overall color: subtle. Across every look and all three exposures, the average difference was about 2.2 ΔE. At normal exposure, individual looks ranged from about 1.4 to 3.1 on average.
• Saturation: slightly lower. Colorful patches came out 3% to 14% less saturated depending on the look. Apple Wide Gamut stores the same scene color with less extreme RGB values, so a Rec.2020 LUT reads it as a little less saturated.
• Blues and violets drift the most. They get lighter, lose saturation and rotate toward cyan. These were the biggest offenders, with the chart’s blue patch reaching 18 ΔE on one look at 2 stops over.
• Oranges and yellows drift next. They get slightly darker and duller, leaning a touch toward red.
• Skin moves a few degrees. Skin patches kept their brightness and saturation within about 2 points, but hue shifted around 3 to 4 degrees on average (up to about 7 on some looks) toward red and pink.
• Blue sky leans cyan. The sky patch rotated around 9 degrees toward cyan on average and came out slightly lighter.

And on real footage?

Real scenes are rarely as saturated as a test chart. On an overcast, muted beach clip shot in Apple Log 2, the difference between the Apple Log LUT and a gamut-corrected version was invisible: under one 8-bit code value per pixel on average, with 99% of pixels within 3 code values. You’ll see the drift in neon signs, deep blue skies, saturated clothing and stage lighting, not in everyday daylight scenes.

Do you need separate Apple Log 2 LUTs?

No. The Ypresets iPhone Apple Log LUTs work on both Apple Log and Apple Log 2, and for most scenes you won’t see a difference. Because the curve is shared, the parts of a look that matter most (exposure, contrast and tonal roll-off) behave exactly as designed.

We’re testing converted Apple Log 2 versions in-house. In the same chart test they matched the intended look to within about 0.1 ΔE on average. For now, the tips below get you most of the way there with the LUTs you already have.

Practical tips for grading Apple Log 2 with Apple Log LUTs

1. Check which profile you shot. Look at the Log setting in the Camera app or in Blackmagic Cam before you grade. Mixing up the two is harmless for exposure, but it’s worth knowing when you judge color.
2. Convert the gamut first in DaVinci Resolve, where available. If your version of Resolve lists Apple Log 2 or Apple Wide Gamut as an input, add a Color Space Transform node before the LUT. Set the input to Apple Wide Gamut with Apple Log gamma, set the output to Rec.2020 with Apple Log gamma, and turn tone mapping and gamut mapping off. That hands the LUT exactly what it expects. It’s the same conversion we used in our test, and our Resolve grading guide covers the node setup.
3. Expose exactly as you would for Apple Log. The curve is identical, so your exposure habits carry over. In our test the drift grew slightly on brighter exposures, so protect saturated highlights such as neon and blue sky rather than pushing them hot.
4. Watch your saturated blues. If a blue sky or blue clothing looks a little pale or cyan after the LUT, a small hue and saturation nudge on blues fixes it. Skin usually needs nothing, but a tiny warm-to-neutral hue correction brings it back if you’re matching shots.
5. Don’t mix profiles in one sequence without checking. If you cut Apple Log and Apple Log 2 clips together, grade a saturated shot from each side by side and make sure your blues match.

New to applying .cube files? Our LUT installation guide covers DaVinci Resolve, Final Cut Pro, Premiere Pro, CapCut desktop, LumaFusion and Blackmagic Cam. For the bigger picture, read Apple Log vs Apple Log 2: what they are and which look to use and iPhone 18 Pro and Apple Log: what creators need to know.

FAQ

Do Apple Log LUTs work on Apple Log 2 footage?

Yes. Apple Log and Apple Log 2 use the same log curve, so exposure, contrast and gray balance land where the look was designed. In our chart test the average color difference was small (about 2.2 ΔE), with the visible drift limited to very saturated blues, violets and oranges.

Is the Apple Log 2 curve different from Apple Log?

No. Apple’s developer documentation describes both profiles with the Apple Log curve, and OpenColorIO implements Apple Log 2 with the same transfer function. The difference is the gamut: Apple Log uses Rec.2020 primaries and Apple Log 2 uses Apple Wide Gamut.

Do I need a conversion LUT for Apple Log 2?

Not to get a good result. For most scenes the difference is hard to see. If you want the most accurate color on saturated subjects, convert Apple Wide Gamut to Rec.2020 with a color space transform before the LUT, where your editor offers Apple Log 2 as an input.

Will an Apple Log LUT change my exposure on Apple Log 2?

No. Grays came out essentially identical in our test (never more than 0.65 ΔE), because both profiles share one curve. Expose Apple Log 2 exactly the way you expose Apple Log.

Sources

• Apple Developer Documentation: AVCaptureColorSpace.appleLog2 and AVCaptureColorSpace.appleLog (primaries and curve for each profile).
• OpenColorIO source: AppleCameras.cpp (Apple Wide Gamut primaries from Apple’s Apple Log 2 white paper, and the shared Apple Log curve).
• OpenColorIO: OCIO 2.6 release notes (adds Apple Log 2 and Linear Apple Wide Gamut).
• Chart tests: Ypresets measurements using the published Apple Log curve and primaries, a standard 24-patch color chart and CIEDE2000.