FiLMiC LogV2 increases the dynamic range of the iPhone XS and iPhone 11 series cameras up to 12 stops in ideal conditions. Here’s how it works.
The engineers at FiLMiC Pro have combined Apple’s AI powered imaging dynamics with their own computational imaging module called “Cubiform”. The result is improved dynamic range and optimized color encoding when using the new FiLMiC LogV2 profile in the FiLMiC Pro app. FiLMiC LogV2 works on all iOS devices and most Android camera 2.0 API capable devices.
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Early iPhone XS Max Tests
In September 2018 I had the opportunity to test the iPhone XS Max with the FiLMiC Pro team in Barcelona. We used the latest build of FiLMiC Pro at the time, which wasn’t yet optimized for Apple’s new hardware. It was an interesting experience to say the least. A lot had changed in the XS generation iPhones. It became immediately clear that the FiLMiC team had a lot of work ahead of them.
I shot an impromptu and unplanned video a day or two after the iPhone XS Max dropped into Apple stores. While it showed a hint of the potential in Apple’s new hardware and image processing, it was difficult to color correct and grade. Apple’s new dynamic tone mapping was fighting with the app’s own image processing, resulting in very inconsistent shots.
Apple’s new image processing seemed like Voodoo at the time, but things have become much clearer in the months since.
Fast forward to November 2018. I started testing a secretive build of FiLMiC Pro incorporating a brand new custom computational imaging module. This module, called “Cubiform” had been in development for quite some time.
Now this is known as FiLMiC LogV2.
One thing has become very clear in the months of testing FiLMiC LogV2 on the latest Apple devices. Using a reference chart, such as the X-Rite ColorChecker Passport Video is the best way to ensure consistency in color correction. FiLMiC Pro is now optimized for Apple’s new image processing, but there can still be inconsistencies and shifts that are tough to correct without a fixed reference.
iPhone 11 Pro Max and FiLMiC LogV2
I’m seeing the best results I’ve ever achieved in post production with FiLMiC LogV2 on the iPhone 11 Pro Max (and this also includes the iPhone 11, and iPhone 11 Pro). Below is an example that was shot with FiLMiC Pro in LogV2, with white balance locked at 5200K using the daylight preset.
The color correction and grade is a great example of a very organic film like look I’ve been striving to achieve for years. This is a new color workflow that I intend to share freely after some more tweaks and tests. It incorporates FilmConvert Nitrate, which is hands down the best film emulation plugin money can buy regardless of what camera you shoot with.
What is FiLMiC LogV2?
The performance of the latest Apple processors allows the FiLMiC Pro engineers to perform more complex math in real-time. The new algorithms in FiLMiC Pro work to complement Apple’s new dynamics and smartHDR, not fight against it.
This results in up to 12 stops of dynamic range from the iPhone XS, iPhone XS Max and iPhone XR under ideal conditions. Even the iPhone SE and iPhone 6S Plus get a 1 to 1.5 stop boost when using the FiLMiC LogV2 profile, approaching 10 stops of dynamic range. I don’t have test data from the iPhone 11 generation cameras at this time.
I don’t have first hand experience of how FiLMiC LogV2 is performing on Android devices but the results seem to be similar.
FiLMiC LogV2 Dynamic Range Test Charts
First let’s look at the charts, then I’ll explain a bit about how this is achieved.
As you can see, the latest generation iPhones show a notable increase in dynamic range. Even the iPhone SE without a neural engine manages an extra stop of dynamic range when shooting with FiLMiC LogV2.
Dynamic Range Test Methodology
The tests were performed with a Xyla 21 stop dynamic range testing chart in a light sealed room. All test footage was captured at 4K extreme (H.264) with a framerate of 24fps and a manual white balance of 3800K. Electronic stabilization was disabled.
Below is FiLMiC Pro’s testing methodology as officially documented.
- The smartphone was held approximately 5-7cm from the Xyla chart with the lens positioned over the third f-stop, which was used to set exposure (we purposely chose to over expose stops 1 and 2).
- Digital zoom was then employed from the rocker so that f.stop 3 completely filled the frame to aid in setting exposure.
- Exposure was then locked, and the image was zoomed all the way back out.
- We used our live analytics to confirm f.stop 3 was correctly exposed, with f.stop 2 and 1 clipping.
- The smartphone was then placed in a tripod approximately 2.5 feet from the Xyla test chart.
- A clip using the ‘Natural’ profile was recorded.
- A clip using the ‘Log’ profile was recorded.
- Clips were imported to a computer using iTunes File Sharing to ensure a lossless transfer.
- Using Premiere Pro CC 2019, natural and log clips were composited on top of one another in a new sequence and exported as a still image frame.
Optimized 8-bit Color Encoding
FiLMiC LogV2 is silky smooth to color grade. It resists the banding and other artefacts of a conventional 8-bit log gamma encoding. Also, FiLMiC LogV2 is not as desaturated as you’d expect. This is because luminance and chrominance are processed separately.
Only when grading some extreme styles did I need to employ some debanding on skies. With a lot of normal looks, this would not be necessary.
FiLMiC LogV2 is close to the limit of what can be done with 8-bit 4:2:0 video from a smartphone.
Beyond this Apple would have to allow or enable encoding to higher video color bit depths. LG and Sony are both making moves in this direction. It seems inevitable that Apple will follow.
How FiLMiC LogV2 Works
FiLMiC Pro doesn’t simply reduce global contrast on an already baked in video stream. If this was the case, the result would be a huge compromise in recorded image information and quality. Furthermore, the problems associated with manipulating 8-bit encoded video in post would be made even worse.
Instead, FiLMiC Pro translates the source 8-bit luminance and chrominance information into a 64-bit space. This information is used to model an expanded luma and chroma map in a mathematical process called gamma vectorization. The result, is a computed fidelity greater than the 8-bit precision of the individual source RGB elements.
Finally, this 64-bit scalar representation of the image is mapped into an 8-bit container for encoding. The output bits are in fact brand new, sampled from the model rather than directly from the source input stream. The resulting image is made up of brand new optimized pixel values, preserving more overall dynamic range and better tonal coherence.
How does FiLMiC LogV2 hold up in post?
Over the past months I’ve shot many tests, mostly with an X-Rite ColorChecker Passport Video under a variety of conditions. I’ve over-exposed, under-exposed, shot with and without ND filters. As long as white balance and exposure are correct, FiLMiC LogV2 is capable of producing truly excellent images.
FiLMiC Pro LogV2 holds up to under exposure quite well, within reason. However, there is no possible recovery of clipped highlights. For the best results in post, carefully watch any highlights that you want to protect. There is little room for error, and limited room for correction, but there is enough room, as long as you take the time to white balance and expose correctly.
I’ve created two video tutorials and written up an article to teach you exactly how shoot with FiLMiC LogV2 and color correct easily by using the X-Rite ColorChecker Passport Video: Shoot and Color Grade FiLMiC LogV2 with the X-Rite Colorchecker Video
FiLMiC have a deLog lut and deFlat lut available for download that help give you a good starting point to getting your video close to Rec.709. You will still need to tweak things after applying the lut in order to line everything up on the scopes. The lut is useful if you don’t use a reference chart, but not necessary if you do.
FiLMiC LogV2 Tips
Here are some tips to use FiLMiC Pro LogV2. The two most important factors to get right are white balance and correct exposure.
- Invest in an X-Rite ColorChecker Passport Video chart.
- Use the ColorChecker grey card reference to set and lock white balance often. The light can change quickly outside and throw off your color. Always position the grey card reference so it is evenly illuminated by your key light source or full ambient light. Use the zoom function to fill the frame with the grey card.
UPDATE: While the above is not technically incorrect, I have actually found the most consistent color for shot matching and color correction can be achieved by using the FiLMiC Pro white balance presets. In all outdoor conditions I’m locking the daylight 5200K white balance preset. This is currently giving me very consistent color, making shot matching and color correction far faster in post.
- Shoot your ColorChecker color chart at the beginning of each camera setup or position. Ensure the chart is illuminated evenly by your key light source or full ambient light and is clearly visible in the frame. Lastly, avoid reflections in the black reference chip to ensure you get a clear black point reference.
- FiLMiC Pro’s exposure reticle works very well, you can place it over the brightest area of the image, and lock it once set. For example, this is often the brightest part of the sky or a white object. Set and lock your exposure after locking white balance.
- Record the highest possible bit-rate “FiLMiC Extreme”.
- Avoid high frame rates for maximum image quality.
- Download your FiLMiC Pro video files using iTunes, don’t ever save or export to the iOS camera roll.
UPDATE: As of iOS 13 I’m airdropping files to my Mac from the phone using Files app.
- You can use the FiLMiC Pro deLog or deFlat lut as a starting point for color correction in post if you find it easier.
- Use your recorded XRite Video ColorChecker Passport chart as a reference to make corrections to levels, hue and saturation for each shot that you have recorded a chart. This will guarantee a technically correct Rec.709 image.
FiLMiC LogV2 Exposure Using A Variable ND Filter
The video below explains the best way I’ve found to expose correctly and consistently. Relying only on FiLMiC Pro’s manual adjustments of ISO and shutter speed can cause problems with Apple’s image processing. The best way to control iPhone video exposure without upsetting Apple’s dynamic tone mapping is to use a good variable ND filter. I’m using the PolarPro Peter McKinnon Edition Variable ND filters but any variable ND filter will work, they just vary in quality depending on price.
FiLMiC LogV2 and FiLMiC Flat do not correct identically.
It’s best not to mix FiLMiC Flat and FiLMiC LogV2 video as there are differences in tone even after manual correction using the chart. It is possible to match them with more adjustments. However, this can be time consuming and tricky.
Extreme high contrast and backlit scenes.
Very high contrast backlit scenes can cause severe problems. This is because Apple’s dynamic tone mapping and smartHDR attempts to reduce extremes of contrast. In some cases, it will raise shadow and midtone levels too close to highlight levels. The result is an unusable image that cannot be corrected.
UPDATE: This problem has been largely solved with the iPhone 11 generation devices, and I believe has improved on the iPhone XS generation devices with iOS 13.
FiLMiC Pro’s “Cubiform” image processing combined with Apple’s smartHDR and dynamic tone mapping result in a very usable high dynamic range image when using FiLMiC LogV2. However, shifts in exposure and levels still result in inconsistencies.
These inconsistencies can be corrected easily by shooting and color correcting using a reference chart. FiLMiC LogV2 video also responds well to creative color grading. In conclusion, excellent results can be achieved when these methods are followed.
- Learn more about computational imaging and the future of mobile imaging.
- Find out the best way to get perfect iPhone video exposure in FiLMiC Pro using a variable ND filter.
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