GH4, Cinelike-D and the Myth of iDynamic

GH4, Cinelike-D and the Myth of iDynamic

First of all, take a look at the latest video I shot on the GH4. The daylight footage was shot using the Natural profile with Contrast at -3. I wanted to see if I could get good results on something other than Cinelike-D. 


Boulevardia GH4 from Todd Norris on Vimeo.



My conclusion is that Natural produces skin tones that are a bit more lively than Cine-D. They look warmer without over saturating other objects in the frame. And highlights roll off more gracefully in Natural. One thing to be aware of: Natural produces an image that is 2/3 stop brighter than a Cine-D image shot at the same exposure. This is because the mid tomes are lifted and the setting is generally more contrasty. However, if you use zebras, and intentionally underexpose your Natural shot by 1/3 to 2/3 of a stop, you can get a very pleasing image with the same dynamic range as Cine-D. You'll just need to bump up the the exposure a little in post.

Will I still use Cine-D? Yes. Especially at night or in scenes with a lot of black in the frame. Cine-D with Contrast at 0 produces a great image in these scenarios that sometimes needs no grading at all. If the frame already has a majority of dark shadow areas, Cine-D produces deep blacks but with a rich tonality as it rises into mid tones. No grading needed.

This shot is an example:

The Myth of iDynamic

For whatever reason, people have been using iDynamic in an attempt to get a flatter, more "LOG-like" image out of the GH4. Most users have been disappointed with the noisy results and have turned iDynamic off. I agree completely. The noise iDynamic produces outweighs any benefits. Take a look at the images below for proof. 

I went to a location scout and shot this test at 400 ISO, not realizing I had iDynamic set to HIGH. Look at the noise in the shadows. This is 400ISO!

Compare that to a shot at 800 ISO, with iDynamic set to OFF, shot at the same location. One full stop higher ISO, but much, MUCH less noise in the shadows. I'd even dare say this is a good shot. Had I used iDynamic, it would have been ruined.

iDynamic. Just say no!

Grading 8-bit 4:2:0 footage from the GH4

What's interesting about the GH4 is that, if you look at the numbers, it shouldn't grade very well. The 100mb 4k at 8-bit 4:2:0 should have macro blocking and banding if you push it too far. And to some degree this is true. But the truth is that I can push it farther than GH2 or GH3 footage. I chalk this up to several things. Improved dynamic range. Lower noise sensor. And the Cine-D profile. And the zebra setting which has helped me keep exposure in line.

Here's where I have a bit of a split-personality. The pragmatic cinematographer in me is saying "get the look in-camera, don't shoot flat". But another part of me is looking at the flat Cine-D footage that I have shot. I'm thrilled at the final result once I grade it in post.

My conclusion is that, as long as you have good instincts and get a decent exposure, the GH4 is a good enough camera that it can handle both approaches. Getting the look in-camera or shooting flat and grading later…it can handle both. Just don't shoot TOO flat or go crazy with lifting the Master Pedestal.

Below shows an image I shot in Cine-D. For the record, I used a bounce card and two reflectors to shape the light on his face and reduce overall contrast.

Ungraded:

Contrast Curve applied (note the gaps in the waveform monitor):

Final grade using curves and Magic Bullet Looks (gaps in waveform monitor go away):

So, even though I can see gaps in the waveform monitor, I don't notice any degradation to the image. And when I add my final grade, it looks great. The GH4 is very malleable. Perhaps if you are used to shooting RAW, the camera might seem inflexible, but compared to what I am used to, it is amazing.

The Myth of Master Pedestal

One final topic. Master Pedestal. Again, for whatever reason, some GH4 users have decided to crank the Master Pedestal up to +15 in order to get a flatter image. I won't go into detail here why I think that's a bad idea, but allow me to point you to the flat, ungraded picture of the man above. This was in Cine-D with Master Ped set to 0. Look at the waveform and see where the blacks fall. Between 20 and 30 IRE. This is already such a low contrast image that, had I set the Master Ped to +15, it would have squished it into an even narrower range, and it would need an even more extreme curve and black crush to get it to look normal. The fact is, on the shot above, I should have LOWERED the Master Pedestal to set the blacks lower. 

If you shoot with filters, or on bright sunny days, or in heavy backlight, you are going to get light flaring into the lens which will lift the blacks. Why lift them even more with the Master Pedestal? Bottom line is that it won't give your image any more dynamic range or make it easier to grade.