using grey card

[mathews]

what is the lighting conditions most suitable for using the grey card. can i use it in bright sunlight to get a meter reading or in shadows. is an overcast day all right for using a grey card. please help.

 

[Alpha]

Any lighting condition is suitable for using a gray card. That's the point of the gray card.

 

[shmne]

The beauty of the gray card is that regardless of what colors are lurking around the world, you can trust that your card will stay the same color within its life span.

This lets you say, regardless of light, that that card is gray. When you are in photoshop this means that you can use the curves adjustment to color correct your scene by using that card (as well as a source of white and black in the scene)

 

[Boomn4x4]

^ +1

What you are asking is the same thing as, "what temperture is ideal to use a thermometer?"

 

[Flash Harry]

basically your cameras meter renders everything 18% grey, (not 12%), green as in grass, is also mid range in colour, hence why a reading from grass or a grey card will give correct exposure for the lighting in the scene you shoot, as long as the reading was in the same light and as long as you lock exposure on the card or grass before firing at the subject. Once you grasp the basics of the meter, (being a liar basically) then you know to overexpose for whites, dependent on how bright the scene is, 1, 2 ,3, stops etc or underexpose by similar for darker colours and shadows. H

 

[mathews]

basically your cameras meter renders everything 18% grey, (not 12%), green as in grass, is also mid range in colour, hence why a reading from grass or a grey card will give correct exposure for the lighting in the scene you shoot, as long as the reading was in the same light and as long as you lock exposure on the card or grass before firing at the subject. Once you grasp the basics of the meter, (being a liar basically) then you know to overexpose for whites, dependent on how bright the scene is, 1, 2 ,3, stops etc or underexpose by similar for darker colours and shadows. H

but doesn't colour change under different lighting conditions.

 

[Boomn4x4]

but doesn't colour change under different lighting conditions.

You aren't metering "color"... you are metering available light. The color is irrelevant. Blue can reflect 18%, red can reflect 18%, yellow can reflect 18%... you could just as well use an 18% red card, and 18% blue card, or an 18% yellow card... people just use gray because its a simple color to make.

Your exposure dosen't have ANYTHING to do with the colors, it has to do with how much light is available.

 

[mathews]

red is 18%. yellow is one stop lighter than red so it cannot be used as a grey card.

 

[Bitter Jeweler]

the internets is full of experts

 

[Willl]

the internets is full of experts

Yeah that's why everything on the internet has to be true.

 

[mathews]

red is 18%. yellow is one stop lighter than red so it cannot be used as a grey card.

Okay... in all seriousness... which one do you think is going to *reflect more light*? (which, by the way... as already has been stated... is what the grey card is all about...)

A knitted, matte yellow sweater?

http://knitblog.com/biggeek/images/Knit Yellow Jacket.jpg

Or a red car?

Imageshack - lotus1u.jpg

I mean... someone call me out on being totally stupid... but to me that one just seems like plain ol' common sense...

to be frank, i am totally confused myself.

 

[Boomn4x4]

red is 18%. yellow is one stop lighter than red so it cannot be used as a grey card.

There is no reason you cannot have a shade of yellow that reflects 18% of light.

 

[KmH]

Gray comes in different shades, but the key is that Gray tones are charcterized by having equal amounts of red, green and blue. in other words, no color casts. A grey card is also used to set a custom white balance.

Pure white is 255 (red), 255 (green), 255 (blue) Pure black is 0 (R), 0 (G), 0 (B).

 

[Aye-non Oh-non Imus]

I've only recently gotten a balance card. Grey one side, White the other.

Using the grey side, I understand it should be positioned at / near the subject. Would it be best to shoot a full frame of the card or back off to the framed composition?

What conditons do you choose to meter the grey side or the white? Why?

Cheers

 

[Alpha]

I prefer 50,0,0