I need help understanding some concepts (cinestyle, 4:2:0/4:2:2, LUT)

[nedyken]

I'm pretty new to a lot of this stuff and unfortunately there are certain things that are still slightly confusing to me.  I'm doing my best to learn this stuff with the available resources, but I could really use some help understanding some concepts.

I'm using a Canon 5D Mark II.  I have ML firmware installed.  I am using the cinestyle picture profile.  I'm editing with Final Cut X.   

#1 - LUT:  I'm still having a little trouble understanding the purpose of a LUT... not to mention, the LUT doesn't seem to be available to download on Technicolor's website anymore and LUT Buddy doesn't seem compatible with Final Cut X.   With Mark II/Cinestyle footage (and all footage, really), I can color correct directly in Final Cut X.  I typically just use the histogram and waveform monitors and then just raise my highlights so they are just below 100 and drop my shadows so they are just above 0.  I increase the saturation a little.    Why would I need to use LUT Buddy and a LUT? What is it doing that my color correction process isn't covering?  Doesn't it just add a curve (which i'm doing manually by modifying highlights/shadows?)

#2 -  I've read some people mention their workflow includes complicated process of converting footage from 4:2:0 to 4:2:2 color space.  I'm a novice when it comes to this.  What is that doing and why is it necessary?  At the moment I'm just capturing video with the Mark II, importing the files directly into FInal Cut X, manually color correcting ... and that's it.  What's the purpose of this 4:2:0->4:2:2 conversion process... and if it's necessary how should I go about doing that?

#3 -  When actually capturing footage with Cinestyle, I've read a couple mentions of overexposing/underexposing intentionally specifically in regards to using Magic Lantern.   I couldn't get a firm grasp on what people are talking about.  When I'm capturing footage with Cinestyle/Magic Lantern I'm usually just looking at the ML histogram and waveform.  ON the waveform I make sure I'm just below the top line.  On the histogram, I'm making sure I'm just to the left of the right edge.   Do you mean to say that I should have the waveform peak a bit over the top line and on the histogram I should be slightly to the right?  Why is that?  Does cinestyle mess with the way exposure is read on those meters?   

Any clarification would be greatly appreciated.  Apologies in advance for my noobish ignorance.   

I should mention that I'm completely new to DSLR in general.  I barely have any idea what the hell I'm doing.  I took some test clips the other day in a dimly lit birthday party.   I was using the stock 24-105mm lens... I had the cinestyle profile selected (which gave all my clips a very flat grey haze).  Then I just imported those clips directly into Final Cut X, raised the highlights, dropped the shadows, increased the saturation a bit and exported it out.  I'm wondering what steps I'm missing.  Here's the result of that exercise:  https://vimeo.com/55335045 

[Francis]

#1 As far as I understand, you are right. The Cinestyle LUT is essentially just a curve to reintroduce the reduction in contrast that was taken out by the Picture Style. LUTs obviously can be custom made so they are probably more important when matching footage from multiple cameras in a large production when post is handled by multiple people or groups of people. I am a photographer more than videographer so I don't have a ton of experience w/ video color correction and post work but I never liked the results from using Cinestyle w/ the provided LUT.

#2 Just like upsampling with stills, using a larger color space allows more room for editing before the signs of your editing can be seen. Examples of overediting include banding and noise in shadows. A good experiment is comparing a 8bit greyscale gradient from black to white versus a 16bit gradient from black to white as you apply equivalent and successive levels adjustments in photoshop or some other editor. You end up with a blockier gradient and bands much much faster on the 8bit image than the 16bit image. Check out this article. The gradient experiment I mentioned is featured about halfway down the page. Also when I do any extensive video post using FCP7, I convert the h.264 footage to ProRes422LT not so much for the increase in color depth, but for the native handling and playback. Less need for rendering to preview is a good thing even though the difference in hard drive space is substantial.

#3 These cameras' sensors put out the best output when exposed to the right, like you are doing. There is much much more detail retained in the highlights regions that can be recovered as opposed to shadows. You still don't want to blow your highlights but setting say zebras to 98% or 99% and look for those danger zones or expose to the white line in the waveform view but not over it. Those meters are reading what Cinestyle is outputting so they are as close to accurate as we can get for an in-camera waveform or histogram.

All in all, in my unexperienced and humble opinion, you are doing all the right things and understand what you are doing. It is definitely a whole lot to take in.

Good luck.

[nedyken]

Thank you Francis.  It most certainly is a lot to take in and unfortunately I'm self-taught in everything I do.  Every once in a while I feel like I'm missing details.   I appreciate the information.   

[dude]

To 3#:
This does not make any sence, because you have to apply the lut in post.
The only way to do it right is to record with cinestyle, and set live view to a picture style that comes close to the wanted final result. So you do your corrections on the "normal style", and record via cinestyle.

By the way, cinestyle should only be used with hard light conditions, darkness etc.
Otherwise you should always use a picture style that comes close to the wanted result.
You cant do much in post with 8 Bit 420....

[jordancolburn]

#1 - The LUT provides a convenient easy way to map the flat recorded data and approximate the final "look".  In big productions it might be applied between the camera output and a field monitor to give a director a better sense of the shot and avoid the "flat grey" look.  As stated above, the way to do this in ML doesn't involve a LUT, but setting the liveview picture style to something approximating the final look and the record style flat.  This method allows you to set focus and exposure properly, then record flatter to give a little more lattitude in post.

#2 -  This article, http://www.hurlbutvisuals.com/blog/2010/12/in-praise-of-dissent-adobe-cs5-paves-the-way/, seems to suggest that in Premiere at least, the internals of premiere are processing the DSLR footage with 4:2:2, so there is no need to convert.  Final Cut may vary.

#3 -  It is better to underexpose slightly because once something is 100% white, it is gone.  A good way to avoid this is by setting zebras.

this article, http://www.hurlbutvisuals.com/blog/2012/01/7-tips-for-hd-color-correction-and-dslr-color-correction/ seems to have the best workflow for correcting flat recorded DSLR footage. 
Don't forget to sharpen in post too.  The flat styles usually turn down the in camera sharpening so you can adjust it to taste in post rather than having it baked in.  That's what all of this mainly comes down to.  For quick easy family moment recording, use standard and save yourself the headache.  For artistic use where you want more control and have the time, use a flat style.  I prefer the prolost settings rather than a cinestyle because it's very easy to set quickly on any camera.


I'm pretty much new too, just thought I'd share some things I picked up from searching around.  Hope it helps!

[Francis]

To 3#:
This does not make any sence, because you have to apply the lut in post.
The only way to do it right is to record with cinestyle, and set live view to a picture style that comes close to the wanted final result. So you do your corrections on the "normal style", and record via cinestyle.

I don't use Cinestyle anymore and never really used the LUT because it mostly looked like garbage but the idea of this and flat picture styles is to decrease the dynamic range to pack in as much detail as you can. So if you are metering and exposing using a Standard picture style, but recording w/ a flat style, you aren't getting the most of what you are recording.

For example, you are exposing using Standard and some shadow region which shows as completely underexposed. You adjust your exposure accordingly. Now you switch to Cinestyle or Neutral or whatever with the contrast turned down to record but this style might have been able to record the scene w/ no underexposed areas without you having to adjust the exposure. Don't you want your exposure tools to tell you what you actually are recording, and not "what it might look like" after doing post. That's what the meters in your editor are for.

Like I told the OP I don't record a lot of video but I shoot a lot of photos. Even though I shoot RAW, I always double check to that my PictStyle is on Neutral, so that the histograms, zebras, and other exposure tools are showing me more closely what the RAW is going to look like, not what the Standard w/ +2 sharpening and +3 contrast or whatever JPEG preview is going to look like. This is also the point of UniWB, setting a WB that more closely mimics the real histogram of the RAW image before any processing is done. If I know that I haven't blown highlights or crushed blacks, I can get the contrast and range I want in post w/o loosing any details.

I might be missing something here, though. I learn more about photography every day.

[nedyken]

Yeah I think I get what dude is saying to a certain extent.  If I was a cameraman working with a director who wanted a very specific look, I'd probably want to achieve that look first (using one of the contrasty picture styles), expose accordingly, make sure the director was pleased with it... and then switch over to a flat style.

But I think I'm leaning towards what Francis says here.  I'm a one man production team.  Anything I work on will be shot by me and edited by me.  Maybe it's a terrible habit to get use to this process, but I think what I'd probably do is just set to a flat style and expose so that I wasn't losing anything in my whites.   At least personally, I don't mind not seeing the "final result" on the LCD.  I just want to make sure I'm getting as much detail as possible and then I can easily tweak it later.  If I drop the shadows a bit and introduce black additional black, it's not going to hurt the image much... but if I start out with crushed blacks, I'm not getting those back.  It seems I'd want to just make sure my highlights weren't peaking (using the mentioned zebras, histogram and waveform).

I appreciate all of the information even if some of the opinions conflict.  I'm getting a better understanding of what I'm doing.

Thanks for the tip about sharpening.  In that test clip I shared, I hadn't sharpened at all.  I use Final Cut X... this is a really stupid question, but since Cinestyle has me drop sharpening -4, does that mean I should add the "Sharpen" effect in Final Cut with an amount of 4.0?  Would that bring back the amount of sharpening I lost or is it a different type of scale? 

[jordancolburn]

But I think I'm leaning towards what Francis says here.  I'm a one man production team.  Anything I work on will be shot by me and edited by me.  Maybe it's a terrible habit to get use to this process, but I think what I'd probably do is just set to a flat style and expose so that I wasn't losing anything in my whites.   At least personally, I don't mind not seeing the "final result" on the LCD. 

I think the goal is not to see the "look", but to set the exposure and focus accurately, because the flat style will not give you as much information on the screen because everything is squished in the middle to preserve more info for editing.  ML makes this easy, just set standard/vivid/whatever as the LiveView picture style and any flat style as the Rec picture style and ML automatically switches just when you're recording.  Very handy!

does that mean I should add the "Sharpen" effect in Final Cut with an amount of 4.0?  Would that bring back the amount of sharpening I lost or is it a different type of scale?

Different units, Sharpen until it looks good, but be sure not to overdo it.  It does make a huge difference, and my general rule is to dial it in until it looks good and I can see the effect, then back off slightly.