OM-1 Video: first findings and Image Quality comparison

[abgestumpft]

I have done some intensive testing on OM-1 Video the past days. For this test alone of comparing the different modes (codecs, framerates, resolution,…) I've shot 81 clips in different settings.

General findings:
-Shutter button does not work for AF in Video (seems to have no function at all)
-AF-ON can be assign to a button, but it will then focus with "hunting" -> can be used for initial AF before Video is started. During Video it's better to use the touch AF -> this will do a smooth transition.
-Object AI AF can be used in Video, but only when AF is set to C-AF+TR. When Video recording is started, there are two different behaviors, depending on Setting: AF->2.AF->AF Area Pointer:
1. On1: when Video recording is started, the white box around the object will be replaced with the green box we know from the C-AF+TR of the other Olympus cameras
2. On2: when Video recording is started, the white box around the object will disappear. But you will see the small green AF Boxes were it focuses on.

-I have not yet tested the AI AF in Video -> to be seen if it works as good as in Photo mode...
-Video Mode can NOT be assigned to a custom mode (C1-C4)
-I was able to set a custom target mode, but I'm not able to select it in Video mode -> here I only can select four standard target modes.

Wrong bitrates:
-Bitrates shown in camera of all SlowMo modes are wrong (see last image in this post)
-Bitrate of FullHD h264 ALL-I seems to be wrong too (102Mbps instead of displayed 202Mbps)?

Image quality:
-Most 4K/C4K modes (all h264 and h265@152Mbps - 50/60 fps) look very similar (in terms of detail) to EM1.3 4K 30p 102Mbps
-there is no difference in details between C4K and 4K (like it was for EM1.2/EM1.3)
-4K/C4K h265@77Mbps - 24/25/30fps look noticeably more detailed than all other 4K/C4K modes -> maybe a little better than EM1.3 C4K. So 4K h265@30fps - 77Mbps looks more detailed than 4K h265@60fps - 152Mbps.
-all HD modes (except SlowMo) look very similar in terms of Detail (h264/h265 - LongGOP/ALL-I - …)
-all HD SlowMotion modes also look very similar to each other and have less detail than the normal HD modes (and have a slight crop vs normal HD modes)
-IS1 (Sensor + Digital) does a crop and image Quality looks almost as good as IS2 (Sensor only). 4K h265@30fps IS1 (Sensor + Digital) looks better than 4K h265@60fps - 152Mbps IS2 (Sensor only)

High Framerate thoughts
-Not sure why the 60fps/50fps modes in h265 don't look as detailed as the 30fps modes. Maybe processor is not fast enough for video processing at those speeds?
-Also: why is there no 4k @120fps -> we get this in foto RAW
-Why is the image quality in HD@120fps not as good as 60fps HD (can't this even be down sampled from 4K/120p?)
-If my math is correct, the Sensor should be able to do 1920x1440 @ 320fps (via crop 1:1 pixel readout)

Zebras/Histogram
-min. Zebra setting is 80 -> cannot be used for skin tones. Wish there was 60 and 70 too.
-Max Zebra setting is 109 -> works well as overexposure warning in HLG and OMLog400: When Zebra 109 in HLG/OMLog400 shows clipping on OM-1 screen the final Video will also show clipping there.
-Histogram changes when enabling "View Assist" in OMLog400 mode (gets stretched). But still works to judge the exposure: also here highlights clip at the same time.

HLG vs OMLog400 (in h265 10bit)
-Both seem to have the same dynamic range
-OMLog400 always needs to be graded (for SDR and HDR)
-HLG looks excellent out of the box on HDR screen supporting HLG (should be 4K TVs staring 2018)
-It is also said that HLG should look good on SDR screens, but I don't agree with that: While brightness is OK (still a bit too dark though) the colors are flat and especially the shadows have a greenish tint -> e.g. also faces look strange…
-But HLG can be graded to SDR e.g. in Davinci Resolve Studio
-I did some testing with grading to SDR of HLG and OMLog400 in Davinci Resolve Studio and found that both work well (did not see a disadvantage for HLG being a broadcasting format here). BUT: I'm not an grading expert!
-OMLog400 and HLG have different Gamma curves (did not find details on this), so one might have the advantage over the other in highlights or shadow work
-Image preview on screen of HLG looks a little like OMLog400 with "View Assist" on (midtones a little darker and shadows a little brighter)
-Autoexposure and Auto WB work well in HLG and OMLog400

Conclusion so far:
The most detail is with 4K/C4K h265@77Mbps - 24/25/30fps (in HLG or OMLog400). Since HLG looks great on TV out of camera and I'm able to grade HLG in Davinci Resolve to good looking SDR I will now be shooting in:
4K h265@77Mbps 30fps HLG. I have set Zebras to 109 to judge where highlights will be blown out.
I also prefer the overall look of the h265 (HLG and OMLog400) graded footage: it looks more natural than the h264 with Picture Profile.

Here some screengrabs:
HD SlowMo Clips were taken one day later.


EM1.3 - 4K - h264 - 30p - 102Mbps


EM1.3 - C4K - h264 - 24p - 237Mbps


OM-1 - 4K - h264 - 30p - 102Mbps


OM-1 - 4K - h265 - 30p - 77Mbps - HLG graded to SDR


OM-1 - 4K - h265 - 60p - 152Mbps - HLG graded to SDR


OM-1 - HD - h265 - 30p - 22Mbps - HLG graded to SDR


OM-1 - HD - h265 - 200p to 25p SlowMo - 22Mbps - HLG graded to SDR




Wrong Bitrates in ALL SlowMotion modes in OM-1

 

[abgestumpft]

Here three screenshots from the Waveforms in Davinci Resolve of the same scene shot from tripod with SDR (h264 8bit), HLG and OMLog400 (both h265 10bit).

My take is:

on SDR you can clearly see how the highlights are clipped. HLG and OMLog400 have more details there.
When comparing HLG to OMLog400 it first looks like OMLog400 has more headroom in the highlights. But when comparing them they are just compressed more on the HLG footage. Brightest white point should still be roughly the same.
In my tests with HLG and OMLog400 using the same scene I was able to grade them to look very similar.


SDR - h264 8 bit




HLG - h265 10bit




OMLog400 - h265 10bit





df

 

[photoski]

Looks interesting, but serves as a reminder to me how little I know about the video capabilities of my cameras. :-O

 

[abgestumpft]

This is my setting I use in Davinci Resolve Studio (=paid version) to transform the Gamma and Color of the OM-1 HLG to SDR (e.g. for h264 8bit export).

In color tab add a node and use "Color Space Transform" and select those settings:



This will fix the color and also the Brightness will look better -> you can use this as starting point and continue with Exposure, Contrast, Color,...

 

[Joe Lynch]

Thank you very much for this. I need to spend some more time studying your results and experimenting on my own.

Only testing I have done was a runtime test on one battery and one 256gb v90 card in 4k60p and I got 2-1/2 hours continuous on the OM-1 with no signs of heating. Screen flipped out, 70F room temp. One file. No time limit, no heat problems, no file splits.

 

[Techuser]

How's the 1080p? Does it still looks like upscaled 720p?

 

[abgestumpft]

How's the 1080p? Does it still looks like upscaled 720p?

I would say in 1080p there is no improvement.
Here some screengrabs:


OM-1 HD 30p h265 ALL-I




OM-1 4k 30p h265 downscaled to HD




OM-1 4k 30p downscaled to 720p and then upscaled to 1080p

 

[abgestumpft]

Thank you very much for this. I need to spend some more time studying your results and experimenting on my own.

Only testing I have done was a runtime test on one battery and one 256gb v90 card in 4k60p and I got 2-1/2 hours continuous on the OM-1 with no signs of heating. Screen flipped out, 70F room temp. One file. No time limit, no heat problems, no file splits.

Thanks. I totally forgot that we have "unlimited" recording and no splitting of files with the OM-1 now. Especially that there is no splitting of files is really helpful.
I don't think I will ever record 2,5h but it is good to know it is possible.

 

[abgestumpft]

Here is a comparison of 4K - h265 - 30p - 77Mbps - HLG (=video with the most details) with a 20MP RAW in Workspace exported to JPG and then downsampled to 4K width (3840px). The colors / contrast /... is different (since two different programs are used and one comes from RAW, the other from 10bit video). But when you compare the details, it's impressive how close the 4K video is to the downsampled 20MP image. Here is a 100% crop for comparison:


4K - h265 - 30p - 77Mbps - HLG (without grading)


4K - h265 - 30p - 77Mbps - HLG - Grading in Davinci Resolve Studio (-> compressed a second time as video)


20MP RAW downsampled to 4K width (3840px):

 

[Joe Lynch]

That grab frame looks really good to me. I didn't expect it to look that good at all.

 

[Adah Wu]

This is my setting I use in Davinci Resolve Studio (=paid version) to transform the Gamma and Color of the OM-1 HLG to SDR (e.g. for h264 8bit export).
In color tab add a node and use "Color Space Transform" and select those settings:



This will fix the color and also the Brightness will look better -> you can use this as starting point and continue with Exposure, Contrast, Color,...

Thanks, this finally solved my problem (along with other more detailed guides). I can confirm that this works with the free DaVinci Resolve version.

What your post lacked was more detailed steps for new DaVinci Resolve users. I finally learnt from other places that I can drag the "Color Space Transform" setting from Effects (top-right corner of the Color tab) to a node. Then your picture gives the rest details.

 

[MarkyM]

Thank you for this!

I assume also that DaVinci Resolve's Color Management Project Settings would need to be set like this, correct?



I ask because there are other HLG settings in there for both Timeline color space and Output color space:



Thanks again!

--Mark--

 

[MarkyM]

Also, should the other nodes (for other adjustments such as color and contrast etc.) be placed before or after the node for Color Space Transform (which is acting like a LUT, correct?) ie. on the HLG or Rec.709 side?

Thanks!

 

[MarkyM]

Oops, the Output Color Space needs to be Rec.709...but which one?

Rec.709 (Scene), Gamma 2.2, Gamma 2.4 or A?

I'm thinking it should be Rec.709 Gamma 2.2 since the output setting in the Color Space Transform node is Gamma 2.2, correct?

 

[MarkyM]

After experimenting for a while, I decided to use OM-Log400 instead of HLG for shooting.

See the new thread I made for the details. Super simple!

--Mark--