FLOG(OPCSDEFS) Optical Printer Control System FLOG(OPCSDEFS)
NAME
flog - configure fader's logarithmic movement
SYNOPSIS
flog [value] # value is a signed floating point number
# (-2.0 is recommended for NORMAL fades)
DESCRIPTION
Sets characteristics of log function used to calculate fades. This
command lets you harden the log curve, or 'soften' it to almost linear.
Values for FLOG are normally negative, since it is usually desirable
to have a sharper curve on the OPEN end of a fade.
In the NEGATIVE range, FLOGs that approach -1.0 force the curve to
become more linear, whereas values that approach -10000 (lowest value
recommended) harden the fading curve on the OPEN end (normal).
In the POSITIVE range, FLOGS that approach 1.0 force the curve to
become more linear, whereas values that approach 10000 (highest value
recommended) harden the fading curve on the CLOSED end (giving a comical
'zip' to/from black).
Values between -1.0 and 0.0 (and values between 1.0 and 0.0) cause
a linear fade, which is more or less a DISSOLVE.
TABLE OF FLOG VALUES AND THEIR EFFECT ON A 12 FRAME FADE
<---- FLOG VALUES ---->
FRM | -50 | -20 | -5 | -2 | 2 | 5 | 20 | 50
----|--------|--------|--------|--------|--------|--------|--------|-------
1 | 3.70 | 4.68 | 7.29 | 10.44 | 19.63 | 30.39 | 53.86 | 70.66
2 | 7.75 | 9.78 | 15.12 | 21.34 | 37.81 | 53.96 | 80.99 | 96.28
3 | 12.21 | 15.39 | 23.57 | 32.75 | 54.73 | 73.22 | 99.26 | 112.29
4 | 17.19 | 21.61 | 32.76 | 44.72 | 70.56 | 89.50 | 113.07 | 123.96
5 | 22.81 | 28.60 | 42.83 | 57.30 | 85.43 | 103.60 | 124.16 | 133.16
6 | 29.26 | 36.57 | 53.96 | 70.56 | 99.44 | 116.04 | 133.43 | 140.74
7 | 36.84 | 45.84 | 66.40 | 84.57 | 112.70 | 127.17 | 141.40 | 147.19
8 | 46.04 | 56.93 | 80.50 | 99.44 | 125.28 | 137.24 | 148.39 | 152.81
9 | 57.71 | 70.74 | 96.78 | 115.27 | 137.25 | 146.43 | 154.61 | 157.79
10 | 73.72 | 89.01 | 116.04 | 132.19 | 148.66 | 154.88 | 160.22 | 162.25
11 | 99.34 | 116.14 | 139.61 | 150.37 | 159.56 | 162.71 | 165.32 | 166.30
12 | 170.00 | 170.00 | 170.00 | 170.00 | 170.00 | 170.00 | 170.00 | 170.00
♀
Or as a graph:
FLOG=-50
Frame (Slow Close/Fast Open)
12 : x
11 : x
10 : x
9 : x
8 : x
7 : x
6 : x
5 : x
4 : x
3 :x
2 :x
1 o.................................o
Fader Positon
CLOSED OPEN
---------------------------------------------------------
FLOG=-1 through 1
Frame (Linear Close/Open)
12 : x
11 : x
10 : x
9 : x
8 : x
7 : x
6 : x
5 : x
4 : x
3 : x
2 : x
1 x.................................o
Fader Positon
CLOSED OPEN
---------------------------------------------------------
FLOG=50
Frame (Fast Close/Slow Open)
12 : x
11 : x
10 : x
9 : x
8 : x
7 : x
6 : x
5 : x
4 : x
3 : x
2 : x
1 x..................................o
Fader Positon
CLOSED OPEN
BUGS
FLOG values above 10000 or below -10000 blow out the software with a
range error when you try to shoot a fade. Keep values out of this range.
Versions prior to K1.16 did not handle values between -1
and 1 correctly, i.e. did not generate a linear curve.
This was fixed in K2.00 (Aug 2020)
SEE ALSO
OPCS Commands
CAM(OPCS) - shoot camera (fades/dissolves too)
OPN(OPCS), CLS(OPCS) - open/close fader shutter
SHU(OPCS) - move fader to an absolute position in degrees
DXI(OPCS), DXO(OPCS) - set up dissolve in/out
FDI(OPCS), FDO(OPCS) - set up fade in/out
OPCSDEFS Commands
FLOG(OPCSDEFS) - set Fader LOGarithmic curve for custom fades
FRANGE(OPCSDEFS) - set fade/dx's degrees range (for Hicon film stocks)
INTERP(OPCSDEFS) - set interpolation positions (fader, focus, etc)
SLOP(OPCSDEFS) - correct for slop in a motor (fader, focus, etc)
General
MATH(DOCS) - math expressions (for use in frame specifications)
SYNTAX(DOCS) - online calculator and OPCS math expression syntax
ORIGIN
Gregory Ercolano, Los Feliz California 12/14/89