9.14.2014

How to suck the color and life out of a video file from a GH4 and then write an absolutely awful review of the camera.

Right off the bat I'll admit two things: I know that the 4K video of the GH4 camera is somewhat noisy at ISOs of 800 and over. Not deal killer noisy but noisy in the shadows. I will also admit that I am not a veteran video colorist. But I'll make the point that this lack on my resumé gives me some advantages over the people who grew up in the video and motion picture film business by allowing me the ability to come at new the paradigms of video with a cleaner slate.

Before I jump into it I want to present an conundrum from the our collective transition from actual film to digital and how we changed our practices. When we shot transparency film we routinely "metered for the highlights." That meant, practically, that we were frightened to over expose our film and lose our highlights to "clear film" (the 255+ of yesteryear).  We slightly underexposed our slide film to make sure we had ample detail in the highlights and we let the shadows fall where they may. Or we filled the deep shadows with light from flashes or reflectors.

When we started shooting with digital cameras we ported over the same mentality and it made sense. If you stepped over the line at 255 you had blown highlights and they were never coming back. But digital was different from film and weak, noisy shadows were the result when we started pulling up the shadow area exposures in post processing. Then we discovered the practice of ETTR (or expose to the right) which pushed us to expose brighter and move the histogram closer and closer to the right hand side of the scale to precisely nail highlights while bringing up shadows into a usable range. Now we have raw files with lots more latitude for highlight and shadow recovery. Almost like negative film. Most of us are no longer paranoid about blown highlights and our images look great. It doesn't hurt that the latest Sony sensors are beasts when it comes to the lower part of the tonal scale and resist noise almost as effectively as my wallet resists hundred dollar bills. We're now through with the last century methodology of shooting a processing. We have successfully changed the way we shoot and process and we get better quality images as a result.

So, what does this have to do with the GH4 and video? Well, the GH4 gets slammed for two things. The first is noise and the second is that the files don't do well in the older and pervasive paradigm of video shooting and post processing. If you thought still photographers in the early days of digital were a bit nervous about losing highlight detail the video guys were scared to death about having too much contrast and too much saturation in the files. The saturation was an issue because once it was baked into a file it was hard to match up the file to broadcast standards which called for shoving files with normal gamuts into extremely tiny broadcast standard gamuts.  The same with contrast. The tiny sensors that most of the video cameras used fell apart with high contrast scenes.

At the same time film shooting cinematographers got used to using negative stock to shoot features. They could slightly (or profoundly) overexpose the negative (c-41) film stock while shooting and then compensate when developing to create an image that was more or less bullet proof to over exposure or too much contrast or saturation. That made it easier to shoot contrasty scenes and the idea was that color saturation and overall contrast could be more easily handled in post processing.

Now we're in the future. We have cameras that can shoot pretty wide ranging scenes without requiring special handling. And the newest computer monitors can deliver two or three (or four) stops more dynamic range than CRTs and old TVs.  But what old schoolers are doing is setting up their new video camera the same way they did in the bad old days; to their lowest contrast, lowest sharpness and lowest color saturation levels; in effect sucking out 90% of the information in the files, the math... and then bitching when they can't restructure the information in Final Cut Pro X, DaVinci Resolve or Premiere to look as good or better than the info they just sucked out.  It's just a bit insane.

The video mavens are overlaying antiquated techniques to the new tools for no other reason than because THAT'S THE WAY THEY'VE ALWAYS DONE IT. 

But it doesn't have to be that way. We don't have to start with damaged footage to make content that looks great on screen. I may not be as smart as the online cinematographers but I can look at files and methodologies and make tests that tell me today's video cameras, be they Alexa's or GH4's were created to make beautiful images----in the cameras. And all of the editing tools I just mentioned will take those perfectly exposed, nicely tonal mapped and medium saturated images and make absolutely great video files. In an absolute sense they can look better because they don't have buckets of vital information (pixel data) stripped out of them before use.

I do get the logarithmic progression used by S-Log profiling and understand that it does provide real increases in dynamic range but the DR will still need to be compressed to reside in most display gamuts. The problem with the old method is that it works best with huge raw files from dedicated video cameras and not as well from the more fragile files from more conventional in-camera codecs. But these are the kinds of codecs most people will turn to when they make their video work at this point in time. If you are outputting 10 or 12 bit uncompressed raw files from your camera into a outboard digital recorder you probably know what you need to do to hit your targets and you don't need to listen to my advice but I think about half of the "flat world" videographers do things in this fashion for.....fashion, and because the higher level of voodoo tends to create a barrier to newbs.

I just read a review of the GH4 written by the assistant of a famous (and very good) cinematographer who complained that the files they worked with, battered and butchered by the ancient but revered process, looked like... video. Not filmic. I would challenge this cadre and, in fact, I would challenge video experts all over the world to take the risk and embrace the modern tools exemplified by smaller cameras and DSLR cameras and use them the way they were designed to be used to deliver great results. To my mind that means creating really good looking files in the cameras and sending them into the edit universe instead of sending artificially flat and desiccated files.

In the comment section of this poo-poo video review of the GH4 the famous cinematographer repeated over and over again that the camera 'didn't make it' in the process he normally uses. But I'm also guessing he wouldn't get great results souping his transparency film in Reisling wine either. My take is that people under think and over think at the same time. I even wonder if anyone in his shop bothered to stick a fast card into the camera and shoot some footage at its default settings. I'm wondering if they had used the camera as the makers of the camera intended whether or not they would have been more (and unexpectedly) impressed. Here's my take:

Shoot at the right exposure setting. Make a good and accurate custom white balance. Set the saturation at its default or "natural" or "neutral" setting. Choose a contrast setting that works well without throwing out the "data babies" along with the bathwater. And then do an "A-B" test of this with their current methodology, along with the usual post processing "magic" they like. You'll have more control over exact saturation levels in post. You might like a bit of contrast in your images, I know the viewers do. Without a true S-Log profile setting in-camera everything else is a joke because the camera compresses with a much different and more destructive methodology that ruins non S-Log files. No way around this. It's like trying to run a Jpeg through a raw processor and not understanding why you can't make huge correction shifts without consequences!

As I said at the top, I am not the consummate video editor or colorist. I don't have the years of experience (and indoctrination) that many others do. I may not even be right. I could be missing a huge step here.  But I do know digital files and they never come back together again at the same quality once you step on all the parameters and suck out information. Perhaps this works in a RED raw file but not in any of the consumer/prosumer cameras. And not with mainstream codecs.

Don't believe me? Try this: Take your Canon, Nikon, Panasonic, etc. still camera and set every control to its absolute lowest setting. Click the adjustments all the way to the left in sharpness, contrast, and saturation. Then go an shoot a portrait or a landscape or a street scene in Jpeg. Come back to the studio and open that file in PhotoShop and then try to make it look like a good image using every tool in PhotoShop. Should be an interesting experiment. Same with the video part of cameras.

Here's an interesting read: http://www.xdcam-user.com/2013/03/to-shoot-flat-or-not-to-shoot-flat/

Curious what my video experts here have to say on the matter.

I know, I know. Most of you could care less about video and care even less about nonsense like codecs and video profiles. Patience, my friends. We'll circle back to real photography soon enough.

A dispassionate look at the differences between the GH3 and the GH4. Not in the lab but out on a job.

The King Kong, Mr. Spock and Beyoncé of the Micro Four Thirds Universe.
This is a must have if you are shooting m4:3 for a living.

Blog reader, David E., asked me in an e-mail just what the differences are between the GH3 and the GH4 and whether or not the GH4 was worth the extra $1000 represented by current pricing models between the two cameras. Interesting that I should come home last evening to that question because I spent the day shooting both of the cameras side by side. Same subject matter, same lighting and the same ISOs and settings.

It's been a full week of shooting and post processing at VSL. If you are a regular reader you know that I had a four day shooting assignment that started one week ago. That was followed by a full day of post production and comparisons between three cameras, the Nikon D7100, the Panasonic GH4 and the Olympus EM-5.  After studying my results I started packing for the full day of photography we did yesterday. 

In many ways the assignments were quite similar. Both were conferences about finance and business but yesterday's conference was about diversity and mentoring for minority MBA students at colleges like Harvard Business School, The Kellogg School, The Tuck School of Business at Dartmouth and many more. The job brief called for a range of images to include team building exercises under mixed lighting, speaker and panel photographs, audience reaction shots and coverage of the keynote speaker's address to the group. The project took place at the meeting and conference facilities of a global financial services company which hosted the 120+ students as well as speakers and facilitators. 

The group started at the crack of dawn with the arrival of the attendees right at 7 am. Yes, I was there by 6:30 to scout, do some preliminary custom white balances of the three major areas we'd be photographing in and also to meet, face to face, with a brand new client.

98% of what we shot was done with available light but we did sneak in some flash on the group shots of 120 people.

In my camera bag were only two camera bodies and only two lenses. I brought the GH3 and the GH4 along with the 12-35mm f2.8 X Vario lens and the 35-100mm f2.8 X Vario lenses and used them interchangeably for everything. I brought a dedicated Olympus flash (600r) which I never took out of the bag and a Yongnuo XXX (manual only) which I used at half power, bounced off white ceilings or at full power bounced off the ceiling in the big conference room for the group. I wish we could have done the group shot outdoors because the facility has a wonderful outside amphitheater but we had a wonderful, soaking rain yesterday and (delightful) sixty degree weather. 

I used both cameras in their manual modes and both lenses mostly between f2.8 and f4. I stayed in the 1250 ISO range except for my group shots, which were done at 400 ISO. While there are subtle differences in image quality in favor of the GH4 the noise looks very similar (small, black grain pattern noise, no color splotches...) between the two cameras. If you were to judge on image quality only and your use of video precluded the need to go to 4K I'd say you would be very happy using either camera interchangeably and, if you chose the GH3, keeping the extra grand in your wallet.

But life is never so simple for people with too many choices....

So, let's jump into the litany of differences that might make the newer camera more appealing for you. And there are operational differences that make the GH4 more fun and better. I haven't found a single metric by which I would judge the usability of the older camera to be better.

To my mind one of the major reasons to use a mirror less style camera is to take advantage of continuous live view through the EVF of the camera. That makes the quality of the EVF image; its sharpness and accuracy a major part of a camera's capability profile. A poorly done EVF undermines the rest of the experience and if you can't trust its feedback then why go down the mirror less pathway to begin with?

While the GH3 has an EVF that was competitive when launched the EVF area of camera design has evolved very quickly. The GH4 has nearly twice the resolution of the GH3 in the finder. It also is user settable to have double the refresh rate of the older camera's finder. That means less lag and faster response. The combination of higher resolution and faster refresh rate gets one closer to the look and feel of the traditional OVF. And of course both iterations give you all the benefits you want from an EVF including incredible amounts of information in the finder as well as pre-chimping abilities. 

The GH4 finder is just plain better all around. I am better able to see how the camera will deliver the final file while I am shooting. By that I mean that the newer EVF tracks color and exposure more accurately which means I can apply compensations while shooting that preclude the need for excessive (and in some cases, image damaging post processing).  Neither camera is perfect but that is also a result of the human eye making accommodations while trying to incorporate the finder image and the ambient (actual) image simultaneously. The GH4 just does it better. 

While on paper the GH4 has a faster frame rate than the GH3 it's pretty much meaningless to me as I tend to shoot in the S-AF, single frame mode almost all the time. But here's the difference between the two, the newer camera has a faster shutter mechanism and a faster internal processor and that makes the camera seem more responsive. The shutter seems a little more instantaneous and the appearance of a review frame happens quicker. In essence the shutter is real time while the faster processing reduces black out (present in both mirrored and mirror less cameras both, just in different manifestations...).  That makes the newer camera feel more responsive overall. 

Both lenses should be working with the new focusing method of the GH4 and both do seem fast and assured, even under low and low contrast light sources, but I never felt that the GH3 was particularly show to focus. Maybe that is more a result of the way I use the cameras than changes in the cameras. 
I did try using continuous focusing with face detection on both cameras and found that the GH4 gave me a much higher keeper rate (defined by very fast, on the money focusing lock and shoot performance). 

Moving on to file processing.  I shot both cameras in the raw mode because I somehow convinced myself (incorrectly) that I wouldn't be shooting that many frames and since the lighting was low and mixed and the range of complexions ran from light to very dark and I thought I might want some play room for precise noise reduction, etc. I ended up shooting more than 1500 images between the two cameras and, for the most part I ended up with the default noise reduction. I did shoot a few shots in Jpeg for myself to see the difference between the two cameras when setting the iResolution control to the standard setting. The appearance of correct and incisive sharpness was much better on the GH4. I chalk it up to the faster processing and evolution of the camera software. I noticed that the iRes is also functional in raw so I stayed with standard in the GH4 and "low" in the GH3.

I was happy with the camera choices for sharpening in the GH4 and I did some mild sharpening in Lightroom with the GH3 files. 

Looking side by side at similar shots from both cameras at 1250 ISO I don't see a lot of difference between the raw files in color, contrast or overall tonality. 

I chose these cameras for my job because I knew that the fast feedback loop of the EVF viewing and pre-chimping capabilities would be very useful. I enjoy composing on the screen and like being able to see how my settings on the camera will be implemented in the files before I commit. I knew that I could get the quality I needed from both cameras if I was careful to custom white balance and make sure I nailed exposure as well as possible. I did three custom white balances on each camera because the three different auditoriums I worked in each had their own mix of LEDs, fluorescent lights and some small MR-16 tungsten spots.  Working with good custom white balances takes some of the difference between cameras out of the mix. In the auto mode the GH4 is a bit more accurate in most instances than the auto WB in the GH3. Applying custom white balances when shooting minimizes or eliminates that difference. In daylight situations the cameras are equal. It's only under nutty mixed lighting scenarios that I see and difference and I'm not always sure which camera is most accurate or if I'm happily trading accuracy for a pleasing color rendition. Which I almost always prefer. 

Had Panasonic not come out with the GH4 I would probably have kept my 3's (mostly for video) while picking up and EM-1 for the better EVF and image quality improvements. Even owning a GH4 I am intrigued by the allegedly better finder of the Olympus EM-1 and might have to get one. I'm on the fence because the longer I use the EM-5s the better I am able to predict the results of the final images based on that camera's EVF presentation. The sensor in the EM-5 is also very nice for portraits (while the tonal distribution is a bit heavy in the shadows...).

To sum up...and to answer David's question: I was happy to shoot the GH3s and especially happy (thrilled) to shoot 1080p video with them. In fact I think the GH3 and the GH4 are pretty much head to head for many (ample light) video situations in 1080p. I think the GH4 is worth the money if you shoot professionally. The handling and ability to more accurately predict results from the GH4 over the GH3 are the deciding factors for me. The faster, more assured focus and the "crisp" handling feel of the camera are bonuses. 

While I might really love an EM-1 (and I have now, grudgingly, mastered the awful Olympus menus..) I do love the body of the GH series cameras. It fits my hand perfectly for a full day of shooting. 

Wrap up: How do I know I like a certain camera more than others? I shoot with it. If you add up the five days of shooting I did this week I spent over 40 hours with cameras in my hands just this week. 
I spent another sixteen hours picking my way through and post processing or throwing away some part of over 5,000 images. With this kind of use you see what works and what doesn't. After you shoot enough images from any camera you know that your two best strategies are to precisely nail exposures and color balance. No matter which cameras you use a darker exposure that must be pulled up in post always looks noisier and lacks some shadow detail. No matter how great your sensor in your camera is it's always better to absolutely nail color at the time of shooting instead of dicking around in the raw processor trying to find some elusive sweet spot. All the cameras on the market right now have the capability to provide the image quality you need for most jobs. The real issue is usability. That's the point so many people miss. Especially in the arguments around mirror or no mirror. To me it's not really all about smaller and lighter it's mostly about predictability and reliable color.  The EVF is a powerful tool. Much more powerful than smaller lenses. 

But the ability to enjoyably hold and use a camera for a long time+the advantage of real time viewing and pre-chimping is what makes the whole equation work for professional event shooters. The GH4 and the EM-1 are the best of the breed. Get either if you do still work. Get the GH4 if you see yourself doing more and more video work. The GH3 is a generation behind. You'll notice it more if you shoot it a lot. It's a lot like color sense. Humans are horrible at discerning color shifts without a referent but they are extremely proficient at seeing the differences between two things that are sitting right next to each other. The GH3 is a highly capable camera----until you use it on the opposite shoulder from your GH4. 

David, I hope this answers your question!