exposure and white balance (grey card and white card)

[sglion]

Hi,

As far as I have understood, white balance setting is due to the nature of light, as a white card is used for custom white balance setting.


exposure is what the camera decides will be the best for a given photo. So if its a white curtain on sunlight and shot is for inside, it might think the curtains could be overexposed and try to reduce the exposure level, and the camera tries to make it 18% Grey and set its exposure.

So how using a gray card is exposure fixed? like using a white card to set the white balance, how is the exposure set ?

 

[sglion]

I mean is it such that the metering is locked/based to that 18% grey card, and after that refocus and shoot ?

 

[IsenGrim]

grey/white card has nothing to do with exposure.

its for white balance.

what is white balance? it has nothing to do with exposure. it just means your white/grey card will appear white/grey in your image.

your white card can be blue if you shine blue light on it. right? then you can choose to either, let it remain blue, or use white balance to correct it to white.

(or you can use white balance to correct away from white, make something white look yellow for instance)

 

[catchlights]

[vid]RjrYVCwOOrA[/vid]

 

[catchlights]

grey/white card has nothing to do with exposure.

its for white balance.

what is white balance? it has nothing to do with exposure. it just means your white/grey card will appear white/grey in your image.

your white card can be blue if you shine blue light on it. right? then you can choose to either, let it remain blue, or use white balance to correct it to white.

(or you can use white balance to correct away from white, make something white look yellow for instance)

all along (since the heyday of film photography) photographers being using gray card for getting correct exposure.

 

[IsenGrim]

all along (since the heyday of film photography) photographers being using gray card for getting correct exposure.

learnt something new today. i think its something i take for granted given the instant previews on digital cameras now adays.

 

[sglion]

catchlights, Thank You.

 

[daredevil123]

Hi,

As far as I have understood, white balance setting is due to the nature of light, as a white card is used for custom white balance setting.


exposure is what the camera decides will be the best for a given photo. So if its a white curtain on sunlight and shot is for inside, it might think the curtains could be overexposed and try to reduce the exposure level, and the camera tries to make it 18% Grey and set its exposure.

So how using a gray card is exposure fixed? like using a white card to set the white balance, how is the exposure set ?

Simple. Once you get the exposure metered on the 18% grey card, just use the metered values and set your camera to M mode.

 

[Abbot Man]

Simple. Once you get the exposure metered on the 18% grey card, just use the metered values and set your camera to M mode.

Can also do exposure lock; after metering you can lock the expousure without the need to go M mode. Check your camera manual for the AE-L button.

 

[Abbot Man]

all along (since the heyday of film photography) photographers being using gray card for getting correct exposure.

The 18% reflectance of the grey card represents the middle grey tone between black and white and is used as the standard for metering systems..