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Nikon Gamma Controls v0.1 Beta Test
  • LPowellLPowell

    Nikon Gamma Controls - v0.1 Beta Test

    Overview

    Nikon Gamma Controls bring interactive adjustment of the camera's gamma curve to video filming on DSLR's that support Nikon's custom Picture Control profiles. It is comprised of a set of calibrated gamma curves applied to Nikon's built-in Picture Profiles: Neutral, Portrait, Standard, Landscape, Vivid, and Monochrome. Unlike previous custom picture profiles such as Technicolor's Cinestyle, which provides a single, non-adjustable gamma curve that attempts to cover all types of shooting conditions, Nikon Gamma Controls enable the user to select a standardized gamma curve that best suits the illumination of each shot. And since Nikon Gamma Controls are calibrated to industry-standard grading tools, the selected gamma curve can be freely and accurately fine-tuned in a wide range of video editors without loss of image detail.

    Gamma Control - Exposure's Hidden Dimension

    One of the first challenges that confront videographers is gauging the proper exposure for each shot. While modern DSLR's provide a variety of illumination meters and exposure adjustments, high-contrast scenes can easily exceed the camera's limited dynamic range. In these situations it is often necessary to deliberately underexpose the darker areas of a scene in order to preserve highlight details in the brightest areas. This can result in starkly-lit video images that require significant grading to boost the visibility of shadow details. Unfortunately, the darkest areas in videos compressed with 8-bit H.264 encoders are recorded with noticeably degraded image quality, and this imposes a practical limit on the amount of enhancement that can be applied in post-production.

    What is actually needed in these cases are controls that enable the user to set not only the exposure level of the highlights, but to independently control exposure of darker areas as well. When recording video, Nikon cameras convert the RAW sensor data into Rec. 709 video data and compress the scene's dynamic range into a format designed for viewing on consumer televisions. The core mathematical formula used in this conversion is known as the video gamma curve, and it determines the relative brightness of dark and midrange tones compared to the highlights. Broadcast engineers fine-tuned the Rec. 709 gamma curve for television viewing under subdued room lighting - a standard that is not well-optimized for image capture, particularly not for high-contrast lighting situations. For optimal image quality, the camera's gamma curve should ideally be adjusted specifically for each scene.

    The Zen of Gamma Control

    While there are many ways to adjust the perceived brightness of an image, the gamma function has a uniquely valuable property - it enables you to manipulate the proportional brightness of midrange tones while leaving the exposure of the brightest and darkest shades unchanged. That gives you the ability to protect highlight detail with a conservative exposure setting, while independently adjusting the overall brightness of the image with the gamma control. It is literally an extra dimension of exposure control, demonstrated in the video sequence below. The inset histograms measure the change in midrange brightness as gamma is varied from 1.0 to 0.4:

    In practice, Nikon Gamma Controls are a set of seven gamma curves, in this case applied to Nikon's built-in Neutral Picture Profile. I have calibrated the curves with the base Neutral profile as gamma 1.0, decrementing with each step by 0.1 down to a gamma of 0.4. This provides a gamma adjustment range of 2.5:1, covering the full range of practical shooting conditions. The reason I chose this particular scaling is because it matches the calibration of the built-in gamma controls provided by a wide range of video editors. This calibration is so precise that you can grade each of the above clips back to gamma 1.0 simply by applying the same gamma setting that was used to record it. (In other words, to restore a video shot at gamma 0.5 back to the camera's default gamma 1.0 curve, simply grade it with a gamma curve set to 0.5. With a 32-bit video editor, this process is completely reversible - no image details are lost!)

    Improving Image Quality with Gamma Control

    If Nikon DSLR's recorded videos in uncompressed RAW format, there would be no practical advantage to using gamma control profiles. In addition to filming video, Nikon Gamma Controls can be used in JPEG still photography (e.g. to bring up shadow details in backlit photos). If you capture both JPEG and RAW image formats, however, you'll find that the RAW images are unaltered by Nikon Gamma Controls.

    With video, however, the internal H.264 encoder burns the camera's gamma curve permanently into each recording, and it's here that Nikon Gamma Controls can visibly improve shadow detail quality. With a gamma of 0.5, for example, darker shades are recorded with about twice as much mathematical detail as that used in the camera's default gamma 1.0 picture profiles. An additional advantage is that boosting the recorded illumination of shadow details can give you the option of turning down the brightness when grading the video in post, instead of needing to dig image details out of the darkness. The example below shows how grading a video shot at the default gamma of 1.0 produces visibly coarser results than grading with gamma 0.7 or 0.5:

    Nikon Gamma Controls Beta Test Info

    This initial Beta Release of Nikon Gamma Controls has been thoroughly tested for accuracy and reliability on a Nikon D5100. In addition, I've verified proper operation on Nikon D5200 and D7000 cameras (and confirmed that Nikon D3100 and D3200 do not support custom Picture Controls). In addition, I've confirmed compatibility with the calibration of gamma controls provided in Adobe Premiere Pro and After Effects, versions CS5 - CS6.

    My understanding of Nikon's documentation is that all contemporary pro and prosumer DSLR's support custom Picture Controls using a standardized, cross-compatible set of built-in picture profiles. Detailed information on the Nikon Picture Control System is available here:

    http://imaging.nikon.com/lineup/microsite/picturecontrol/catalog/PicCon.pdf

    The reason I'm releasing this version as a Beta test is because there are additional compatibility issues I don't have the resources to investigate on my own. I would appreciate help in confirming support for Nikon Gamma Controls in the following areas:

    • Support for custom Picture Controls across Nikon's DSLR models.
    • Accurate gamma calibration on each of the built-in Picture Profiles.
    • Calibration of gamma adjustment controls in prominent video editing suites.

    With Nikon Gamma Controls v0.1 Beta, I've included the complete set of gamma controls for Nikon's built-in Neutral profile, with default user settings adjusted for video recording. The Neutral profile is well-suited for video and provides a solid baseline for evaluation. Once we have confirmed compatibility with a broad range of Nikon DSLR's and video editing applications, I will generate calibrated gamma control profiles for all six of Nikon's built-in picture profiles and include them in subsequent releases.

    Download and Installation of Nikon Gamma Controls

    I've packaged Nikon Gamma Controls in a zip file attached to this post. After downloading and unzipping it, you'll find a folder named NIKON, which contains a CUSTOMPC folder that contains a set of Nikon Picture Control profiles. Copy the entire NIKON folder structure to the root folder of a compatible memory card and insert it into your camera.

    To install Nikon Gamma Controls, find the "Manage Picture Control" option in the SHOOTING MENU. Select the "Load/Save" option, and then the "Copy to Camera" option. You should then see a list of the Nikon Gamma Controls profiles, starting with one named "Sepia". I included this profile as a convenient placeholder to fill in the seventh slot in the stock "Set Picture Control" menu, at the bottom end of the list of built-in picture profiles.

    If your camera works like the Nikon D5100, it will accept up to nine custom profiles, labeled C1-C9. If you load Sepia into C1, it will be displayed along with the built-in profiles on the first page of the Set Picture Control menu. You can then load the seven Neutral Gamma profiles into C2-C8 slots, and they will all fit neatly on the second page of the menu. When loading each profile, the camera will give you the option to revise the profile name. You need to take care at that point, and press the +Magnify button instead of the OK button, to accept the custom profile without changing its name.

    Usage of Nikon Gamma Controls

    On Nikon DSLR's, video is recorded in Live View mode, and prosumer models work in a quirky manner that can subtly foul up the use of Nikon Gamma Controls. The fundamental problem is that the camera is unable to electronically update the lens aperture after you enter Live View - the lens iris will stay fixed even when the displayed aperture appears to change. In order to reliably set the aperture, you must exit Live View mode to do so.

    Once you've set your aperture (in either M or A-priority modes), and returned to Live View, you may want to lock down your exposure with the AE-Lock button. This will work properly as long as you do not exit Live View mode. But beware, because there's a hidden pitfall - if you snap a still photo in Live View mode, the camera will exit and return to Live View. That will silently invalidate the AE-Lock exposure settings and your video exposure will no longer be correct. To be absolutely sure you're shooting with your intended exposure, always engage AE-Lock just before pressing the movie record button.

    Once those glitches are under control, you can experiment with the seven profiles in Nikon Gamma Controls. As long as you stay in Live View mode, you can interactively select different gamma settings from 1.0 to 0.4, and evaluate their visible effects on the LCD screen. You can also use gamma bracketing - repeating a shot with a range of gamma settings - without leaving Live View between each recording. This is how I recorded the sample videos and it was very quick and convenient to adjust gamma on-the-fly while composing each shot.

    If you examine the user settings in each Neutral Gamma profile, you'll see that I've set Sharpening to 0, Saturation to -2, and Hue to 0. These settings differ from the defaults in the built-in Neutral profile - they're what I found most useful for shooting video. If you experiment with these user settings, be sure to update each of the seven Neutral Gamma profiles the same way. That will preserve your ability to fine-tune the gamma profiles in post, with calibrated grading and intercutting among all Nikon Gamma Controls profiles.

    Nikon Gamma Controls v0.1 Beta.zip
    10K
  • 51 Replies sorted by
  • LPowellLPowell

    Here is an example of how Nikon Gamma Controls can be used to enhance shadow and midtone detail in extreme cases of high-contrast lighting. In the sunlit street scene below, I reduced exposure to produce an acceptable amount of highlight blooming in the sun flare in the upper right corner. As a result, details in the shadow of the skyscraper were underexposed. Using Nikon Gamma Controls, I was able to raise the exposure of shadow details, while maintaining a steady exposure on the sun flare. The waveform monitor display inset at the upper left corner shows how exposure levels across the frame can be precisely gauged using Nikon Gamma Controls.

  • LPowellLPowell

    Reserved for sample video

  • rigsrigs

    Thanks for sharing your hard work Lee. Looking forward to trying this on my d5200

  • tetakpataktetakpatak

    Thank you LPowell, as always, for all your work you are sharing with us.

  • last_SHIFTlast_SHIFT

    Bravo!

  • paglezpaglez

    I'm thinking about to buy a Nikon D800. Is this utility available in this camera?

  • AriaAria

    Wow this is really cool. I'm still waiting for the D7100 to see how it functions before taking a dive with either the D7100 or D5200. Good to know that some development on improvements is already underway.

  • ahblezaahbleza

    I will test these on my D800 this weekend. Thanks @LPowell.

  • LPowellLPowell

    @paglez Yes, the Nikon D800 supports custom Picture Profiles and I expect it to work compatibly with Nikon Gamma Controls.

  • paglezpaglez

    @LPowell Thank you, sir.

  • ulimanuliman

    Hi LPowell. There is so much knowledge that you share since the days of GH1. Thanks for your great work and smart and helpful attitude. Uli

  • cbrandincbrandin

    Nice work Lee! I've been playing around with picture controls on a D800. One thing I noticed is that if you turn Active D-Lighting on it disables any custom curves in a picture control - presumably because the camera is using that function to achieve the Active D-Lighting stuff.

    Another interesting thing I discovered about the D800 is that it doesn't appear to use the High ISO Noise Reduction feature with video. I ran some tests and nothing appeared to change no matter what I set High ISO NR to. This means people will be claiming that the D800 is noisy. Actually, it isn't - it's just not doing noise reduction in the camera with video.

    I've only messed with the D800, so I don't know to what degree other models behave the same way.

  • BlueBomberTurboBlueBomberTurbo

    Just shot some promotional vids at work with the Neutral Gamma 1.0 setting on my D7000. I'll post up shots once I get to processing this weekend.

    Was messing around with all the settings last night, and the 0.4 setting is amazing! Of course, if you're using it in dark conditions, it'll be super chunky, even after NR. But for good lighting, it's insanely flat. I chose the 1.0 for today, since I'll be doing limited grading, but I find the 0.7 to be a nice overall balance.

    @cbrandin AFAIK, High ISO NR never worked in video for Nikons. Didn't on my D90, and doesn't on my D7000.

  • LPowellLPowell

    @BlueBomberTurbo Thanks for confirming Nikon Gamma Controls compatibility with the Nikon D7000. The Neutral Gamma 1.0 profile has the same gamma curve as the built-in Neutral profile (with Sharpness 0, Contrast 0, Brightness -1, Saturation -2, and Hue 0). I included Gamma 1.0 in NGC to provide a precise match with the other gamma curves, and to leave the built-in Neutral profile available for still photography.

  • last_SHIFTlast_SHIFT

    I can confirm that they work on the D800. Unfortunately I am not a testing guru so I couldn't give you any stats or samples. But I shot a daylight scene with .5 gamma and its super flat and I was able to push a really heavy grade.

  • LPowellLPowell

    Check out the second post above for an example of using Nikon Gamma Controls to adjust exposure in the presence of sun flares.

  • olegkalyanolegkalyan

    @LPowell I've tested GH2 against D5200, shot similar scene with GH2, http://yadi.sk/d/1zLrUjpx30Wjs http://yadi.sk/d/oKMziAYm30WlA The links are for original files, please download and make your conclusions, settings: both cameras 3.2k, iso 160, shutter 1/50, F1.8 focus on the lettering on tea bag on the left. lenses on GH2, Leica DG Summilux 25mm f/1.4 ASPH, on D5200 Nikon AF-S Nikkor 35mm f/1.4G

    done another test setting Nikon 0.8 vs. S Hurtado Flaat 11.

    Here are links to new test with Flaat11, I had to open up half a stop on GH2 to match exposure, http://yadi.sk/d/kprDlbBt31RYk http://yadi.sk/d/vjONtqku31Rfo

    Nostalgic all -2 on GH2, Flaat11 on Nikon, not changed. focus on letters on the box.

    both tests makes me think of inherent latitude of camera sensors, that are similar, getting shadows up, does not help protecting luma clipping, watch bright spots on metal parts.

    link to graded video, showing GH2 better resolution. Please do you own tests, and share what you think.

  • LPowellLPowell

    @olegkalyan

    both tests makes me think of inherent latitude of camera sensors, that are similar, getting shadows up, does not help protecting luma clipping...

    In practice, protecting highlights is straightforward: simply lower your exposure until the highlights no longer blink in the Nikon highlight display, or bloom on the right edge of the GH2 histogram, or clip on the top edge of the waveform monitor.

    With most cameras, however, guarding the highlights with a conservatively low exposure setting will produce coarsely-encoded, near-black shadow details. Nikon Gamma Controls give you the ability to boost the quality and brightness levels of shadow and midtone details without blowing out the highlights.

  • olegkalyanolegkalyan

    @LPowell in reality, just raised shadows, with lifter blacks create look that lacks both black and whites on RGB scale, it can be ok for some experimental or wedding videos, leaving footage with this look, low, dull luma.

    In broadcasting reality, one has to bring the signal to broadcast standards, while not completely abide by 16 235 rule, trying hard to achieve that (getting pure blacks, and pure whites in the shot, while not clipping luma as much as possible. (Hello film, or Alexa) That's how most of films, television made. So, in our case, we'd have to work with D5200 material shot with Nikon profile, getting enough chroma, color information, grading it. Upon all the steps, one ends up with pretty similar results, in the case of quick study, comparing GH2 and D5200. The final result, overall range after grading and luma clipping matters, not preliminary. through test needed to prove this POV or otherwise, I state this from my experience of grading, working with material from different cameras, considering final output. Please do you own tests. And thanks again for your hard work!

  • LPowellLPowell

    @olegkalyan Yes, grading for broadcast standards requires you to manipulate the dynamic range to fit into the studio-swing 16-235 range. My experience is that I've gotten better quality shadow detail by shooting with a boosted gamma curve that lifts dark details into the gray region. That allows me to obtain the contrast I want in post by darkening the shadows, rather than attempting to dig shadow details out of dimly lit areas. I think Nikon's Neutral profile works well for video, and the ability to tweak it with Nikon Gamma Controls makes the camera ideal for nighttime available light shooting.

  • mc988mc988

    @LPowell thanks for all the hard work. I've been testing the profiles on my d5100 and they work really well. i noticed there is still a bit of noise though even at iso 100. Do you any advice for getting rid of noise using after effects cs6 or premiere cs6?

  • cbrandincbrandin

    I wonder how contrast vs. curves are handled. It would be nice if the contrast setting is applied before the curve. If it is, you could adjust the dynamic range with the contrast setting (whereas the curve is restricted to redistributing data within a fixed DR). That way it might be possible to emulate the highlight leveling of negative film. For example, suppose contrast is lowered and effectively raised again with a curve - highlights would be rounded thus avoiding being blown so easily. I'll have to figure out a way to test this.

  • LPowellLPowell

    @cbrandin Nikon's Picture Control Utility allows you to select which built-in Picture Profile to use as the base for your custom Picture Profile, but when you select the custom gamma curve option, it disables the Brightness and Contrast controls. These two controls are also grayed-out in-camera when you load and select a Picture Profile with a custom gamma curve. This makes it clear that custom gamma curves are intended to replace the built-in Brightness and Contrast controls. However, Sharpness, Saturation, and Hue controls can be adjusted, allowing you to set default positions for these controls in your custom Picture Profile.

  • cbrandincbrandin

    Thanks for the information Lee. Bummer... it seems that there is no way to affect the total range - just how it is distributed.

  • paglezpaglez

    @Lpowell I would like to know how can I work with this utility and Premiere CS6. What is the utility inside Premiere to adjust final grade process, after using NIkon gamma control? Sorry for my bad english. Is not my native language Thanks in advance.

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