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Bruce Greene

Member Since 07 Feb 2005
Offline Last Active Yesterday, 05:35 PM
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Posts I've Made

In Topic: If a film person goes to digital ...

Yesterday, 05:35 PM

True, I never thought about checking the movies shot with the alexa studio to see if they have the same issues.

I shot one film where we had two Alexas, one digital shutter and the other mechanical shutter.  I don't recall seeing a difference that was distracting in any way.  We ended up with the Studio Alexa as it was cheap as no one wanted to rent it :)

 

I used to shoot on tape based Varicam that had a true global shutter/CCD sensors.  The effect was quite noticeable compared to a film camera with it's rotating shutter, so I don't think you'd like that solution either...


In Topic: If a film person goes to digital ...

21 February 2019 - 07:12 PM

Exactly... which is why the top camera is still and will be the Alexa for many years to come. Arri has figured out a way to capture the dynamic range of film, they've been able to create beautiful skin tones, they've created a camera package that's easy to use AND the look is more cinematic than any other digital cinema camera. You know when you shoot with the Alexa, you're getting a great image no matter what.

It still has the same motion blur issues that drive me nuts tho... I hope someone solves that someday.

I think the motion blur was solved by using the Alexa Studio, with the optical finder and mechanical shutter :)


In Topic: Color calibration and different viewing platforms

21 February 2019 - 12:08 PM

Hmmm.  YouTube material, not mine, generally looks correct on my TV.  I also have the Vimeo app, and my videos on the vimeo/TV combination also look correct.

 

When you upload to Vimeo or YouTube, these services take your original material and re-render it to multiple versions for streaming.  And this is where I think the issue may be.

 

From my experience, I've found that uploading ProRes or DNXhr 4:2:2 gives the best results for re-rendering to the YouTube or Vimeo versions.  I have more experience with Vimeo, and find that they do not to well with 4:4:4 12 bit codecs, hence the recommendation for 4:2:2 ProRes.

 

Also keep in mind that playback through a web browser also changes the look of the image, depending on the web browser.  And playback of your file through the  Quicktime player has problems all of it's own.  But, usually this is where the image looks more washed out.

 

At this point, since you have the festival screening coming up, I would take your versions to a professional colorist, with properly calibrated equipment, to trouble shoot your issues.  It kind of sounds like some video levels vs. data levels confusion going on.

 

If you've color graded your film yourself, using uncalibrated equipment, and without knowledge of the video/data level issues, chances are that you've made some error somewhere in your workflow.  When you brought your project to the DCP house, did you tell them something like "original is REC709, gamma 2.4, full range data"?  They need to know this to properly create your DCP to the correct levels and gamma.  If you are not familiar with these issues, it's time to consult with a pro before your screening.


In Topic: Exposing skin tones on V-log L profile

20 February 2019 - 01:11 PM

Colors don't shift when shooting LOG, unless you clip or expose one color beyond the range of the recording.  For example, if you clip the blue channel highlights, but not the red or green channels, your highlights will shift to yellow.

 

As for other color shifts involving LOG recording, it's not in the recording itself, but in the transform from LOG, to let's say, REC709 by the use of a LUT.  A LUT works by "if the recorded color at this pixel is "x", transform to "y".  So, it's I guess possible that you might see some shifts as your exposure moves out of the range expected by the LUT.

 

But this can be fixed by adjusting the "exposure" of the LOG image before conversion by the LUT.  This is done by "offset" in color correction.  "Offset" simply adds or subtracts the same value from each recorded photosite.  Using this function you can bring the image exposure back into the range that the LUT was designed for.

 

And, in fact, this is the proper way to use a LOG conversion LUT in color correction.  There should be an exposure/contrast adjustment before the LUT conversion, and usually, some color correction performed after the LUT conversion to your output color space (REC709 or P3 etc).

 

There is no "proper" exposure for skin tones.  That's part of the art of cinematography itself.

 

As for YouTube video tutorials... There's a lot of misinformation out there.  If you own the camera, design your own tests and use the free version of Davinci Resolve to check the results.  But, yes, you'll need to learn a bit of the software to do this and it will take some time.

 

There is a lot to learn here technically, and unfortunately, I don't know of a comprehensive book that teaches all of this.  So, you will end up "googling" quite a bit and bumping into a bit of misinformation.  Personally, I began by first learning Photoshop (took about a year!), and applied that knowledge to digital cinema cameras.  It also helps a lot to have a professional color chart for testing purposes.  Good luck!!!!


In Topic: Improvement Besides Being On Set

19 February 2019 - 07:03 PM

From a technical point of view I would suggest doing some experimental color grading in your spare time.  Find some of your original camera footage, hopefully shot LOG format or perhaps RAW.  Use the free version of resolve to play with color correcting the images to see what you can do with them.  Since you're not sending these out into the "real world", you don't need a fancy calibrated display.  Keep an eye on the scopes as you make your adjustments and you'll begin to learn the color response of your camera and it's limitations.

 

If you don't have a powerful enough computer for Resolve, just export some still frames and play with the color and curves in Photoshop.  

 

I promise you can spend many many hours doing this!


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