With the inadvertent pre-release of V-Log L to GH4 owners this week, a number of questions immediately surfaced that focused on noise levels, LUTs, and usability. For me, the most important distinction to be made was how it performed when captured in 8 bit, versus 10 bit. And how it compared to the built-in profiles that the GH4 was released with. Last, I wanted to get to the bottom of these new cyan/magenta artifacts other users were reporting. And I did.
With the V-Log L profile, you are trading tonality for dynamic range. And what are those?
Dynamic Range is the ratio between the lightest and darkest areas of an image that can be captured. V-Log L purports to add two stops of additional range to the GH4.
By Tonality I’m referring to the distribution of available steps or tones in the image. And when more steps are dedicated to gathering more extreme values of light and dark, subtler variations between steps are lost to make up for it.
So I set up a simple frame that would offer extreme highlights to see how much better V-Log L performed there, as well as smooth gradients to see if the sacrifice in tonality was evident, and to what degree.
This series of clips auditions 5 different capture scenarios of a 4096×2160 frame.
All profiles were captured at ISO 400. I know there is debate about which ISOs are noisier than others. But this was not a noise test. This was a look at dynamic range, tonality, and reports of cyan/magenta artifacts in 8 bit captures.
All profiles were set to -5 Noise Reduction and -5 Sharpness. Further, Cinelike D and Natural were set to 0 Contrast, -3 Saturation. In my experience, attempting to shoot “flat” by dropping Contrast to -5 degrades tonality, even in 10 bit.
- V-Log L + V709 + 8 bit + Internal Capture
- V-Log L + V709 + 8 bit + External Capture
- V-Log L + V709 + 10 bit + External Capture
- Cinelike D Profile + 10 bit + External Capture
- Natural Profile + 10 bit + External Capture
You can download the 4K file from the Vimeo page for yourself to get a closer inspection, but my takeaways from this test are:
- With regard to V-Log L, the increased dynamic range over other profiles is clear. But so is the hit you take in tonality. It’s most apparent when gradients in the image are compared directly to the Natural & Cinelike D profiles. 10 bit V-Log holds up the strongest, of course.
- Natural Profile has the best tonality, which makes sense to me as it always seems to produce the most natural skintones. Cinelike is a close second but in use has resulted in a bit of splotchiness and unevenness in skin that I don’t care for.
- In V-Log, 8 bit (both internal and external capture) suffers from cyan/magenta macroblocking evident when the V709 LUT is applied. 10 bit does too, but to an almost imperceptible extent. You probably will have to download the 4K file to see it.
- All samples were captured at the same ISO. V-Log L appears noisier but I have a feeling that if these samples were graded to match, the difference would be fairly minimal. My guess is the higher contrast in Cinelike D and Natural works to suppress the appearance of noise.
- As usual, scaling to 2K improves many of these deficiencies and is another reason GH4 users may want to consider shooting in 4K (or UHD) with a 2K (or 1080p) finish in mind.
So now it comes down to this: do I continue to shoot in the Natural profile for better tonality? or V-Log L for better dynamic range? That’s a tough call. I don’t know yet.