What is it, why are there so many different kinds, and should I be using it? These questions can all be easily answered. If you carefully consider your shooting conditions, equipment and plans for post-production, you can determine whether shooting in log is right for you and which profile is best for your needs.
The subject of filming with a log profile, or logarithmic profile, can be incredibly technical. However, in this article, we will break it down for you so you can understand the basics of shooting log.
What is log?
A handful of leading camera manufacturers provide cinematographers with a logarithmic picture profile. This lets you get a wider dynamic and tonal range than the usual video profile allows. The standard picture profile for full HD video, Rec.709, ensures that all 1080 HD videos look the same on HDTVs worldwide. Rec.709 uses a linear function to record a realistic image with a good amount of contrast and saturation. However, one shortcoming of the Rec.709 profile is its narrow dynamic range. In contrast, log profiles use a gamma curve instead, allowing for more dynamic range.
Basically, dynamic range measures how bright the brightest areas of your image can be in relation to the darkest areas, while still retaining visual information in the highlights and the shadows. If your camera has a low dynamic range, it won’t be able to keep detail in both the bright and the dark areas in a high-contrast shot. In that case, the cinematographer must choose whether to keep detail in the shadows and blow out the brighter parts of the image or keep detail in brighter areas and crush the blacks.
We’re sure you’ve seen amateur video with the subject filmed in front of a window on a bright day. If the cinematographer exposes for the subject’s face, the trees and bushes seen through the window will disappear into a sea of white. Most — or all — information is lost. If the trees and bushes were properly exposed, the subject would be a completely black silhouette with all of their details crushed to absolute black.
We measure dynamic range in stops. The human eye has a fairly high or wide dynamic range of about 20 stops. Today’s video cameras mostly have between 7 and 17 stops, with many around the 10 to 12 stop zone.
Note that not all cameras can shoot log. Here are some of the current leading log profiles and their associate camera brands:
- Log-C on ARRI digital cameras, based on Cineon log gamma (including Log-C3 and Log-C4 — don’t confuse these with Canon Log)
- C-Log or Canon Log on Canon cameras (including C-Log2 and C-Log3)
- D-Log on DJI UAV drone cameras
- F-Log on Fujifilm cameras
- N-Log on Nikon cameras
- REDlogFilm on RED cameras
- S-Log on Sony cameras (including S-Log2 and S-Log3)
- V-Log on Panasonic cameras (including Panasonic, Panavision and LUMIX cameras)
Some cinematographers have had luck with what many refer to as “fake flat.” This is where you make your own neutral picture profile in your menu by bringing down your sharpness, contrast and maybe saturation. Although most camera people will agree that fake flat is not as good as log, you could get some good results if this is your only option.
Why shoot with log?
Log can be a great tool if you know you will have time to edit your footage in post-production. It will help you get more detail in poor or uneven lighting. If you shoot in a run-and-gun style, quickly transitioning from light to dark settings, log is perfect for you. The added dynamic range will give you footage that can be pushed farther than your standard footage. This could potentially save shots from being washed out or too dark.
Filming with a log profile the image to retain more detail in the shadows and highlights of your video footage, but this extra quality comes with a price. To accomplish the feat, the camera, when set to shoot in a log profile, will produce a milky grey, washed-out, dull, desaturated, flat image. Put another way: The shadows are lighter, and the highlights are darker, giving you an image that lacks contrast and looks flat. In fact, log shooting is often referred to as shooting flat.
This footage must then be color-corrected in post-production before delivery. Color correction and color grading are skills that take some time to learn and implement. But, when used correctly, log will allow more room to fix exposure mistakes and give you an option for a more cinematic-looking aesthetic.
One way to avoid color grading is to use a LUT. Simply put, a LUT, or lookup table, is a preset color look for your video footage. Even after using a LUT, most colorists tweak their grading further, but you can drop the LUT on your footage. In addition, you can achieve specific film looks with LUTs. You can make your video have the same color/contrast look as the film “Wonder Woman” (2017) or “Moonrise Kingdom” (2012), for example.
When to shoot log and when not to
If you’re shooting a very high contrast scene that would benefit from a lot of dynamic range, you’re probably going to want to access more of the information hitting your sensor than Rec.709 video will allow. That’s a great time to shoot log. If you are in a controlled environment such as a blacked-out sound stage where you can access an overhead light grid to completely control your lighting, you may not want the extra steps of grading in post-production.
But, although log can improve your video output after post-production, it does present some obstacles while shooting. Most notably, it can be difficult to properly expose while shooting in log. The image you will see when using log in your viewfinder will look washed out and lighter than standard. This makes it difficult to use your experience to properly expose. Don’t be afraid to go back to the basics to figure out how to expose a scene. Exposure tools like your histogram, waveform and/or zebra stripes can be immensely helpful in retraining your eye to the proper settings for any given scene.
Another drawback to shooting in log is additional noise. A helpful technique to mitigate possible problems is to ETR, or Expose to the Right, and overexpose just a hair. Opinions vary, but overexposing your shot by about one or two stops ensures that you won’t need to lift shadows in post — the main cause of additional noise when shooting in log.
Many companies also have an included exposure assist with log in mind. Search your camera to see if there are any built-in exposure assists that will help you set the right exposure settings while shooting in log. Some cameras and external monitors also allow you to load LUTS or the standard REC 709 color space into them and view an image closer to what you will have post color correction. Search your camera for the best options to help you use log to the best of your abilities.
Another time you may not want the extra steps to process log footage in post-production is if you have a quick turnaround schedule. If you are filming news or a wedding with quick delivery times, the extra time needed to grade might not be the best option.
How to shoot log footage
Shoot to the right; you will want to shoot a full stop to as many as two and a half stops overexposed when you are shooting a log. Shooting to the right will pull the shadows up and make it less likely that there is grain or noise in your shadows. The amount you need to compensate depends on how your camera produces log. Research how others who own your camera compensate and/or run tests. Your histogram will be your friend here to make sure you are not clipping important highlights. Remember, once clipped, the visual information in that overexposed area is lost for good.
We also recommend that you shoot in your camera sensor’s native ISO setting. Otherwise, you may still get more grain in your shadows than you care for. If you do capture noise/grain in your shadows, companies like NEAT and Red Giant/Magic Bullet make noise reduction or denoiser software that’s fairly easy to use.
Record in 10-bit. Not all cameras can record in 10-bit internally, so you may need to use a 10-bit external recorder. This will help you avoid banding issues that are common with 8-bit recording. Make sure the monitor works with your specific camera. Many of these monitors come with useful tools such as LUT preview, zebra stripes, false color, focus peaking and histograms. Atomos, Lilliput, Blackmagic, SmallHD and Feelworld all make popular external monitors.
Speaking of preview LUTs, we suggest using them if possible. Some cameras and many external monitors will allow you to load preview LUTs. The milky, dull, flat look of log makes it difficult to focus and get the perfect exposure. Many LUTs are free or inexpensive. Some are created for specific cameras, so make sure they are compatible with your camera setup.
Make sure your editing program is maximized for log editing. Blackmagic Design DaVinci Resolve, Apple Final Cut Pro, Adobe Premiere Pro and AVID are all good candidates. You may need to adjust settings to maximize your log grading. In addition, make sure your computer is strong enough for the high demands of log editing, especially if you are editing 6K or 8K video.
Challenges
Shooting with log is not as simple as pressing the red record button. As we’ve already discussed, shooting log takes time, know-how and attention during production. Do your research, shoot test footage from your camera with its proprietary log profile. Either try grading and/or grade with a LUT.
Also, be aware that many cameras, when shooting at higher than normal frame rates, such as 120 frames per second (fps) or 75 fps, versus the normal 24 fps or 30 fps, might lower the quality of the video to accommodate that higher frame rate. For example, if you want to shoot higher frame rates in order to have smooth slow motion, you may compromise quality to get that higher frame rate. All of this can affect your log quality.
If you pass your footage over to an editor, ensure they have the extra time to grade. Even more importantly, ensure they know how to grade log footage. Be careful not to blame the camera person for poor color work in post-production. Make sure both camera person and colorist are on the same page regarding technical camera settings and deliverables.
Log vs. RAW
As a final note, log is not RAW. To make a complex issue simple, log is a lot like RAW in that it tries to collect more information from the sensor, but they technically go about it in very different ways with very different outcomes.
RAW, simply put, is sensor data before any image processing. RAW is processed and turned into video in the computer, not the camera. Log is video and has some of its video components, such as ISO and white balance, baked into the file.
We encourage you to do more research on this subject if you wish to learn more. Log can be a helpful tool if the setting and demands are right. It can improve your dynamic range and give you more usable footage at the end of any shooting day. But remember, build your confidence before using it on any important shoots. This will give you a chance to see if the extra dynamic range is worth the added post-production work, how to properly expose your scenes and the kind of added quality you can look forward to with log.
Contributing authors to this article include: Morgan Paar and Sky Scholfield.
