: : useful information : :

eric gustavo petersen | cinematographer

tables and charts | useful onset information

t-stops

FULL	1/3	2/3	FULL	1/4	1/2	3/4
0.7	0.8	0.9	0.7	0.7	0.8	0.9
1	1.1	1.2	1	1.1	1.2	1.3
1.4	1.6	1.8	1.4	1.5	1.7	1.8
2	2.2	2.5	2	2.1	2.4	2.5
2.8	3.1	3.5	2.8	3	3.3	3.5
4	4.4	5	4	4.2	4.7	5
5.6	6.3	7	5.6	6.0	6.7	7
8	9	10	8	8.5	9.4	10
11	12.6	14	11	12	13	14
16	18	20	16	17	19	20
22	25	28	22	24	27	28
32	36	40	32	34	38	40
45	50	57	45	48	53	57

1/3 stop increase:	T-stop X 1.1225
2/3 stop increase:	T-stop X 1.26
1/4 stop increase:	T-stop X 1.07
1/2 stop increase:	T-stop X 1.1892
3/4 stop increase:	T-stop X 1.26

The equations come from THE CAMERA ASSISTANT by Douglas S. Hart (ISBN 0-240-80042-7)

incident / t-stop table (click here)

Here's an Incident-to-T-stop chart using the 1/3 stop numbers from the above chart.

The chart assumes the following: 24fps / 172.8° shutter angle (although 170° & 180° can be used)

If you're shooting 24fps @ 144°, use the column to the right (1/3 wider lens stop)

: : 1 foot candle = 10.764 LUX / 1 LUX = 0.0929 foot candles : :

circles of confusion

16mm format:
Normally ranges from 1/2000th of an inch to 1/1000th of an inch. A good average is perhaps 1/1667th of an inch.

35mm format:
Ranges from 1/2000th of an inch for the sharpest lenses and biggest screens, to 1/1000th or 1/714th of an inch for normal cinema projection, to perhaps 1/500th of an inch for 35mm cinematography designed for (analog) television presentation only. Perhaps a good starting point, with modern high-performance lenses and fine-grained stocks in mind, would be: 1/1000th of an inch.

65/70mm format:
Ranges from 1/2000th of an inch to 1/500th of an inch. Perhaps a good starting point is 1/714th of an inch.

A range of useful diameters for the Circle of Confusion:

Fraction of an Inch	Decimal Inches	Millimeters
1/2000 (5/10,000)	0.0005	0.0127
1/1667 (6/10,000)	0.0006	0.01524
1/1430 (7/10,000)	0.0007	0.0178
1/1000 (10/10,000)	0.001	0.0254
1/714 (14/10,000)	0.0014	0.03556
1/500 (20/10,000)	0.002	0.0508