Friday, 5 April 2019

SOME LIGHTING GYAAN : SOME TERMS AND DATA

WHAT IS STOPS?


A stop is a doubling or halving of the amount of light let in when taking a photo or capturing some motion.

"Stops" let you directly compare and swap shutter speed, aperture, and ISO speed to produce the image you want.

OTHER TERMS : 

LIGHT OPAL FROST: 420 Light Opal Frost Diffuses light reducing the contrast between highlight areas. A weak diffusion is similar to Opal Frost less diffuse. Manufactured on a 36-micron polyester base.

HAMPSHIRE FROST: 253 Hampshire Frost
Diffuses light reducing the contrast between highlight areas.

HEAVY FROST: 129 Heavy Frost
Diffuses light reducing the contrast between highlight areas

KELVIN: When talking about photography the term ‘kelvin’ refers to the unit of measurement of color temperature. Every source of light emits light at a specific color temperature which can be measured in degrees Kelvin or ‘K’.

SOME IMAGES :


GRID CLOTH (USED FOR  DIFFUSION)

                                                   TOUGH SPUN 
                                            
                                          MUSLIN CLOTH (BLEACHED)

                                                 
                                            MUSLIN CLOTH (UNBLEACHED)


CHINA BALL (COVERED WITH CLOTH TO DIFFUSE THE LIGHT)



LIGHT LOSS FOR COMMON DIFFUSION TYPES:

White Diffusion "216": 1 1/2 stops


1/2 White Diffusion "250": 3/4 stop


1/4 White Diffusion "251": 1/3 stop


1/8 White Diffusion "252": 1/4 stop

Opal "410": 1/2 stop


Light Opal Frost "420": 1/4 stop


Hampshire Frost "253": 1/4 stop


Heavy Frost "129": 2 stops

Grid Cloth "430" or Silent Grid Cloth: 2 1/2 stops


Light Grid Cloth "432" or Silent Light Grid: 2 stops


1/4 Grid Cloth "434" or Silent 1/4 Grid: 1 stop

Full Tough Spun "214": 2 1/2 stops


1/2 Tough Spun "215": 1 1/2 stops


1/4 Tough Spun "229": 3/4 stop

Artificial Silk: 1 2/3 stops


1/4 Silk: 2/3 stop


China Silk: 1 stop

Unbleached Muslin: 2 stops


Bleached Muslin: 2 stops

Heavy Diffusion:


Muslin, Grid Cloth, 216, Heavy Frost

Medium Diffusion:


Silk, Spun, 250, Light Grid

Light Diffusion:


Opal, Hampshire Frost, 251, 252
LIGHT LOSS FOR COLOR CORRECTION GEL:


CTB (Color Temperature Blue) "201": 1 2/3 stops


1/2 CTB "202": 1 stop


1/4 CTB "203": 2/3 stop


1/8 CTB "218": 1/3 stop

CTO (Color Temperature Orange) "204": 1 stop


1/2 CTO "205": 2/3 stop


1/4 CTO "206": 1/3 stop


1/8 CTO "223": 1/3 stop

CTS (Color Temperature Straw) "441": 1 stop


1/2 CTS "442": 2/3 stop


1/4 CTS "443": 1/3 stop


1/8 CTS "444": 1/3 stop

Plusgreen: 1/2 stop


1/2 Plusgreen: 1/4 stop


1/4 Plusgreen: 1/8 stop


1/8 Plusgreen: 1/8 stop

Minusgreen: 1 stop


1/2 Minusgreen: 1/2 stop


1/4 Minusgreen: 1/4 stop


1/8 Minusgreen: 1/4 stop
MIRED SHIFTS FOR COLOR CORRECTION GEL:
MIRED's are used for calculating color temperature conversions. The math always gets lost in my head so I often use Lee's online MIRED calculator >>>
Here's a link to Rosco's Filter Facts PDF that has a good explanation of the Mired Formula and how to use it >>>

TO INCREASE KELVIN:


CTB  (Color Temperature Blue)-131 MIRED (Converts 3200k to 5500k or 2900k to 5200k)


1/2 CTB -68 MIRED (Converts 3200k to 4100k or 2900k to 3800k)


1/4 CTB -30 MIRED (Converts 3200k to 3500k or 2900k to 3200k)


1/8 CTB -12 MIRED (Converts 3200k to 3300k or 2900k to 3000k)

TO DECREASE KELVIN:


CTO (Color Temperature Orange) +167 MIRED (Converts 6500k to 3200k or 5500k to 2900k)


1/2 CTO +81 MIRED (Converts 5500k to 3800k)


1/4 CTO +42 MIRED (Converts 5500k to 4500k)


1/8 CTO  +20 MIRED (Converts 5500k to 4900k)

CTS (Color Temperature Straw) +160 MIRED (Converts 5500k to 3200k)


1/2 CTS +81 MIRED (Converts 5500k to 3800k)


1/4 CTS +42 MIRED (Converts 5500k to 4500k)


1/8 CTS +20 MIRED (Converts 5500k to 4900k)


References : 





 


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