Gemini 4:4:4 frame Grabs

[Alister Chapman]

Hi all. A very brief post as I've just got back to the hotel from a long day at Broadcast India.

I finally found a little bit of time to upload a couple of quick frame grabs from the Gemini. Sorry they are not Tiff's or the DPX files but time is scarce.

There are 3 frames: The graded S-Log, A Cinegamma 3 grab and the raw S-Log.

The increase in dynamic range over the cinegamma frame is clearly visible in the highlights outside the window as well as on the wall behind the actor.

I have to say I'm liking the Gemini a lot. The firmware is not quite there yet but it's very, very close with almost daily updates being released. Apart from an initial hiccup (which has now been rectified) the unit has been stable even in the Mumbai heat. It amazes me and everyone else that see's it that the little 5" monitor sitting on the handle of my F3 is also a 4:4:4 uncompressed recorder, its so compact compared to all the other alternatives. Being able to apply LUT's on the Gemini is also very neat.

The screen is super bright and easily viewable in direct sunlight. Im powering both the camera and the Gemini of a single Swit S-8U62 battery which gives me a little over 2 hours from a full charge.

It does generate some pretty big files, so I have been using Adobe Premier to transcode the clips to Apple ProRes 4:4:4 on ingest. This is taking a little longer than I expected, but then I am using a vintage MacBook Pro 3.1 and I guess is a small penalty to pay for the incredible image quality that I'm getting.

Combine all this with the soon to arrive EI-SLog firmware from Sony and it will all only get better and better.

[Piotr Wozniacki]

Call me nuts, but out of the 3 grabs, I like the old good Cinegamma 3 the best :)

Of course I realize the S-log could be graded for a more punchy look, but I wonder how the relevant areas (behind the window highlights) would hold?

[Dan Keaton]

Dear Alister,

Thanks for posting.

It is very nice to hear that you like the Gemini 4:4:4.

I am very excited about the new Sony EI-SLog. That is a major advance and makes the already great Sony F3 even better.

[Doug Jensen]

Originally Posted by Alister Chapman

There are 3 frames: The graded S-Log, A Cinegamma 3 grab and the raw S-Log.

Correct me if I am wrong, but the S-LOG and Cinegamma frames seem to be taken at the exact same instant. How can that be? You can't be using a Picture Profile and S-LOG at the same time. So are you saying that the Cinegamma grab is coming from a LUT? If so, that is hardly a fair comparison. There is absolutely no way that a stock LUT chosen from the camera's menu pages is going to provide the same kind of control as a full-blown Picture Profile. Personally, I don't care for the look of any of the built-in LUTs and I also know for sure that my favorite PP would handle the DR better than the example you have posted. Even the S-LOG frame is blown out. Why did you choose not to expose for the highlights outside the window?

Furthermore, even if the Cinegamma setting was coming from a Picture Profile, you cannot expect to expose for both S-LOG and a Picture Profile at the same time. They require different exposure settings, so any frame grab that captures both frames at the same instant is inherently flawed and of no use in judging the merits or either setting. A good comparison would be exposed for one . . . and then the other.

Did I miss something here? Please correct me if I am misunderstanding the purpose of this example.

[Chris Medico]

Hey Doug,

Do you have access to a F3+S-Log?

I would like to shoot a set of charts to show the dynamic range expression change between the S-Log signal and the signal with a LUT applied. It is different but I don't have charts

Here is what I've observed. When I apply a viewing LUT the full dynamic range of the S-Log is not supplied. Both ends of the scale are clipped. The exact amount I can't say but my gut feeling is it is a stop on the bottom and a little more on the top. This is based on using the REC709+800% LUT.

This is really easy to see if you lock the camera down on a high contrast scene and toggle the LUT on and off while viewing the MONITOR port. We set up a shot where we were going from inside shadow out into full sun with bright blue sky with a few clouds. When we toggled the LUT on and off you could see the detail in the clouds completely disappear when REC709+800% enabled BUT the detail was there when the LUT was disabled.

This leaves me with the question - How do you most fairly compare the different gamma curves when they don't record the same amount of dynamic range? Correct exposure to retain highlight detail for S-Log is going to be different from any of the other gamma settings. If you expose for highlight detail in S-Log then highlights will be clipped on anything recorded with a LUT.

[Doug Jensen]

Quote; "If you expose for highlight detail in S-Log then highlights will be clipped on anything recorded with a LUT."

That is the core of what I am saying in my first post. You can't record a LUT, a Picture Profile, and S-LOG simultaneously and expect them all to look good. Impossible. You can only choose one at a time. So any testing where they are recorded at the same time is useless.

Yes, I have S-LOG, a real Leader waveform monitor, and DSC charts. There's more I'd like to say about LUTs, but I'll save my comments until I have done further testing of my own and can prove some of the things I believe to be true about working with S-LOG. It's not as easy as some people would have you believe.

[Steve Kalle]

Originally Posted by Doug Jensen

Quote;
.... S-LOG. It's not as easy as some people would have you believe.

I don't know where you are coming from but shooting to S-Log and editing it is no more difficult than the internal SxS for me. In fact, I find shooting and downloading from the PIX240 to be *easier* and quicker than SxS cards because every computer I use has eSata and/or USB 3 ports whereas only one PC has an Expresscard to PCIe adapter (which I use for SxS).

Speaking of EI-SLog, besides being able to use ISO 800, what else is so great about it?

[Peter Moretti]

Steve, does your NLE have a S-Log LUT or are you just applying a color correction effect that you've made?

[Doug Jensen]

Originally Posted by Steve Kalle

I don't know where you are coming from but shooting to S-Log and editing it is no more difficult than the internal SxS for me.

I am coming from the stand point of someone who chooses NOT to grade, but rather to to get the look I want at the time I record -- and at the camera's full, uncompressed capability. Believe it or not, I am still in the majority out there. Most people outside of Hollywood do not have the time, the budget, or care about the slight advantages of grading. If I always graded everything I shot, then yes, you are correct, S-LOG would be just as much a pain in the ass as any other Picture Profile that requires grading. Fortunately, that is not my workflow. Yours is different, and I appreciate that and would not try to talk you out of it. Two valid approaches to shooting. Different strokes for different folks.

The benefits of S-LOG may very well outweigh the workflow hassles and I may decide it is worth it to grade everyting -- but I have yet to see any examples of S-LOG that prove that to me. I look forward to doing my own testing when the next firmware is available.

[Steve Kalle]

Originally Posted by Peter Moretti

Steve, does your NLE have a S-Log LUT or are you just applying a color correction effect that you've made?

I don't see any need for a LUT because a simple Curves adjustment makes the image look *normal*. All SLog does is remove the various gammas normally applied in order to maximize the dynamic range.

In this post, I show the SLog image from a PIX240 and then the image with a simple 'S' Curve applied to add contrast. http://www.dvinfo.net/forum/sony-xdc...ml#post1688140
FYI, this was with 6 or 12db of gain so ISO 3200 or 6400 - gotta love it!

[Steve Kalle]

Originally Posted by Doug Jensen

I am coming from the stand point of someone who chooses NOT to grade, but rather to to get the look I want at the time I record -- and at the camera's full, uncompressed capability. Believe it or not, I am still in the majority out there. Most people outside of Hollywood do not have the time, the budget, or care about the slight advantages of grading. If I always graded everything I shot, then yes, you are correct, S-LOG would be just as much a pain in the ass as any other Picture Profile that requires grading. Fortunately, that is not my workflow. Yours is different, and I appreciate that and would not try to talk you out of it. Two valid approaches to shooting. Different strokes for different folks.

The benefits of S-LOG may very well outweigh the workflow hassles and I may decide it is worth it to grade everyting -- but I have yet to see any examples of S-LOG that prove that to me. I look forward to doing my own testing when the next firmware is available.

http://www.dvinfo.net/forum/sony-xdc...ml#post1689926
From your video in this posting, the sky looks great but there is very little to no detail in the trees.(I am looking at the thumbnail image) With S-Log, you would get another 2-3 stops of DR which would result in much more detail in the trees. Is that something you personally want? (I yearn for more DR which is why I love S-Log so much)

FYI, I know of a quick and easy way to apply effects to a list of files in After Effects and render to new files. Its something I learned from having to create proxies with burned TC.

[Doug Jensen]

Steve, of course I want more DR, who wouldn't? But in the case of the footage you are referring to, I'd probably grade it right back to the same look I already have. Even though you don't care for it, I actually like the way the trees look. If I wanted more detail in the dark areas of the picture I wouldn't be running my black levels so low in the first place. If I wanted the trees to look the way you would like them to look, I could have done that simply enough by just adjusting my PP. Sure having more DR is good, but that doesn't mean I simply want to give my picture a washed out appearance with nothing but middle tones. I actually like good contrast with nice deep blacks and whites that come right to the edge of clipping. If I can achieve that with a simple PP inside the camera instead of S-LOG and grading, then that is a superior workflow for me.

Don't misunderstand me, I would not be surprised at all to find that S-LOG is superior for certain high contrast situations, but all I'm saying is that I have yet to see the side-by-side proof. Where is the proof? Like I said, I'm hoping to do my own testing just as soon as I have the time. One thing I have learned over the last couple of years is not to assume anything about picture quality based on what sounds good on paper. I have a adopted a skeptical attitude about everything until proven otherwise. Some people apparently have already seen the proof they need about S-LOG, but I have not. I would LOVE to see the proof that makes me a believer.

[Peter Moretti]

Doug,

I think there is ample proof in that S-Log provides more dynamic range. If that DR is useful for how someone likes to work is another issue.


Steve,

I'm aware of doing a curves adjustment. But some examples I've seen of this that can look rather wonky at times. If find this happens mostly in the skin tones.

Also there's the issue standards, or lack there of when exchanging footage. Finally, if I'm mixing S-Log w/ non-S-Log, I have to be sure to apply the curves adjustment to just the S-Log segments--which can be quite a hassle if your NLE doesn't correct source clips but only segments that have been added to the timeline.

Not saying these are deal breakers, but if S-Log is going to be widely used in NLE's, I'd love for it to be more fully integrated.

[Doug Jensen]

Maybe you have seen "ample proof" in real-world situations, but I have not. Test charts are not the real world. And to my knowledge, nobody has really compared a very good, perfectly exposed Cinegamma PP to the same scene with properly exposed (and expertly graded) S-LOG. I guess I'm not doing a very good job of making my point, so I'll just leave it at that. I'll do my own testing when time permits. I'm sure will probably join the ranks soon of those who are sold on the benefits of S-LOG, I'm just looking for some decent examples to convince me.

[Alister Chapman]

The LUT applied image takes the sensor output and applies either REC-709, or HG1, while the S-Log output gives you S-Log.

It is exactly the same thing, if you look at the Cinegamma output on a WFM and compare to S-Log + HG Lut, you'll find them to be the same.

S-Log very clearly gives you a clear 1 to 1.5 stop dynamic range advantage. It's easily measurable. I played with a camera with a Beta of EI-S-Log at Sony Hong Kong yesterday and it's impressive to say the least, although I didn't have any equipment with which to make a meaningful measurement but it was clearly giving at least an extra 1.5 stops over the Cinegammas.

The nice thing is that by using the EI settings at 1600 you can see what the image will look like post grade with a bit of lift/gain in post. This allows you to then deliberately shoot slightly under exposed, knowing that the graded image will still be completely acceptable. This in turn means that you can give yourself more headroom when dealing with a high contrast scene.

While Doug's approach is certainly a very valid one and if it works for him and others then that is what you should do. However there are many situations where your scene has a range greater than 11 stops (the limit of the CG's) and no amount of in-camera tweaking will allow you to capture that in a pleasant way. S-Log gives you a significant increase in what you can capture plus it grades easily and painlessly when recorded in 10 bit 4:2:2 and above. 4:4:4 is preferable as this gives you better colour correction possibilities.

I think the EI S-Log upgrade is a significant one as the reduction in grain due to the lower base ISO will make post production lift/gain in shadows cleaner. Add to that the ability to pre visualise this in camera by adding EI (electronic equivalent) gain to the LUT makes this an extremely powerful tool.