Tag Archives: Compositing

Camera Data

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It’s worth checking out arenafilm who have a detailed database of filmbacks and lens combinations for various cameras.

Also dpreview have a review of sensor sizes for DSLRs.

I’ll try and keep a useful summary here.

Company Model Film Back aspect Pixels
Arri Alexa 26.136 x 14.702 mm / 1.0290 x 0.5788” (Monitoring/EVF) 16:9 3168 x 1782
Arri Alexa 23.760 x 13.365 mm / 0.9354 x 0.5262” (ProRes) 16:9 1920 x 1080
Arri Alexa 23.760 x 13.365 mm / 0.9354 x 0.5262” (RAW) 16:9 2880 x 1620
Red Epic 5120 x 2700

Timecode formula for spreadsheets

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Like it or not spreadsheets are just too useful. Having the right formula to hand can really make things easier. Plus for me writing a bit of code serves to alleviate the tedium of data entry.

This expression will calculate the difference between two timecodes and spit out the answer in frames. Each cell must written using 11 characters in the standard timecode format. e.g.    10:23:07:24

This version works at 25 FPS and will subtract the IN point cell ‘G4’ from the OUT point cell ‘H4’.

((MID(H4;1;2)*3600+MID(H4;4;2)*60+MID(H4;7;2))*25+MID(H4;10;2))-((MID(G4;1;2)*3600+MID(G4;4;2)*60+MID(G4;7;2))*25+MID(G4;10;2))

You can change the frame-rate by swapping the 25 for a different number.

How it works

The MID function simply grabs individual characters from a cell.

MID(H4;7;2)

Will grab 2 characters from cell H4 starting with the 7th character in the string.
E.g. It will grab 07 from 10:23:07:24

MID(H4;7;2))*25

07 seconds * 25 fps = 175 frames

Max exr motion blur setup

3dsMax EXR motion vectors.

The best option is to use the Motion vector G-buffer in 3dsMax.

X : positive is Right – Negative is Left
Y: positive is Down – Negative is Up

In Fusion

3dsMax EXR Motion vector in Fusion

 

Using the G-buffer fusion in is simple.

In the Loader chose the G-buffer channels for the X and Y velocity.

 

Then flip the Y channel in the VectorMotionBlur tool to point the vectors in the correct direction.

 

In Autodeck Composite (toxik)

The Toxik blur tool is actually very cool. The fact that DOF and motion blur are packaged together in one tool is a real advantage over Eyeon Fusion.

This video covers motion vectors in 3dsMax and Autodeck Composite (toxik). But the information can be generically applied. There’s a couple of issues which he fixes in his next video

VideoTip #18 – How to use a Motion Vector pass from MAX’s Scanline renderer!

There’s also a longer in depth look at motion vectors and some fixes if the tools don’t quite behave as they should do.

VideoTip#21 – In-depth view of Motion Vectors from MAX to Composite!

 

LUT confusion

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Its simple really.

Now with latest version of eyeon Fusion working camera LUT’s couldn’t be easier. The profiles are all included. The my new workflow is very simple.

  1. Simple Log to Lin workflow in Fusion
  2. Using Stacked LUTs in Fusion
  3. Using grading artists lut files in fusion
  4. Log Maths: Converting between gain and f-stops

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