White Card & Grey Card

Vinnyvagus

Vinnyvagus

Suspended / Banned
Messages
21
Name
Craig
Edit My Images
No
Hi everyone

I'm quite new to this and have myself a 450D and been learning bits and pieces from this site and watching tutorials over the last 6-8 months but have come across using white cards and grey cards for better looking pictures.

Now am I right in thinking a grey card is for the exposure and white card is to do with the colour balance?

So is it a good idea to use both or more so one more than the other? Maybe use the white card to set my custom white balance in my camera whilst on a shoot and then also using the grey card to help expose the subject?

I just want to make sure I am understanding the point of both these cards and looking for confirmation or if in fact I am incorrect...someone to explain it to me better :)

Also... when using the White Card for custom WB do you zoom in and fill the viewfinder and take the picture in AUTO mode?

With the grey card I assume you can use Manual mode to lock in the aperture first and use the shutter speed left and right so the marker in the VF is in the middle of the exposure slider whilst zoomed into the grey card?
 
You can use a grey card for both, white balance and exposure. As long as the grey is completely neutral, it works fine for setting your white balance.
 
Nick_A said:
I know this is really really stupid and I cant believe i'm going to ask this but why do we use a %18 grey card to set white balance? why not a white bit of card

in fact ignore me I'll do some searching, I've already made a fool of myself :lol:
Click to expand...

they will both work, but the 18% grey will do exposure aswell so is more useful
 
Vinnyvagus said:
Hi everyone

I'm quite new to this and have myself a 450D and been learning bits and pieces from this site and watching tutorials over the last 6-8 months but have come across using white cards and grey cards for better looking pictures.

Now am I right in thinking a grey card is for the exposure and white card is to do with the colour balance?

So is it a good idea to use both or more so one more than the other? Maybe use the white card to set my custom white balance in my camera whilst on a shoot and then also using the grey card to help expose the subject?

I just want to make sure I am understanding the point of both these cards and looking for confirmation or if in fact I am incorrect...someone to explain it to me better :)

Also... when using the White Card for custom WB do you zoom in and fill the viewfinder and take the picture in AUTO mode?

With the grey card I assume you can use Manual mode to lock in the aperture first and use the shutter speed left and right so the marker in the VF is in the middle of the exposure slider whilst zoomed into the grey card?
Click to expand...

Hi Craig. You've got the gist of it, almost ;)

For exposure, use an 18% grey card. This is a mid-grey - elephant grey is the best way I can describe it. It will be close to the mid point of the sensor's dynamic range so will give maximum opportunity for lighter and darker tones to fall either side of it. If you check the histogram of an image of an 18% grey card, that fills the whole frame, there will be one spike in the middle.

You can also use 18% grey for white balance. Any neutral tone will do, that has equal quantities of red, green and blue in it. White is equally suitable and is perhaps more commonly used because you can often find something pure neutral white in real life to take a reading from - white paintwork, white table cloth, that kind of thing. Finding a truly neutral grey in real life is extremely difficult and it's hard to tell just by looking at it.

To set a custom white balance, the card (or target area of the subject) only has to cover the centre circle, which the camera reads from.

That's the basics of exposure and will always get you a usable result, but if you really get into it the question of correct exposure or optimum exposure gets quite complicated and depends on your camera's sensor, the exact calibration, the subject, the result you want, and whether you're shooting for Raw or JPEG output.

The histogram will tell you exactly what's going on. That is generated off an actual image file, so it takes into acount all the variables, whereas any meter reading is only a guess based on a series of assumptions that may or may not be correct.
 
HoppyUK said:
Hi Craig. You've got the gist of it, almost ;)

For exposure, use an 18% grey card. This is a mid-grey - elephant grey is the best way I can describe it. It will be close to the mid point of the sensor's dynamic range so will give maximum opportunity for lighter and darker tones to fall either side of it. If you check the histogram of an image of an 18% grey card, that fills the whole frame, there will be one spike in the middle.

You can also use 18% grey for white balance. Any neutral tone will do, that has equal quantities of red, green and blue in it. White is equally suitable and is perhaps more commonly used because you can often find something pure neutral white in real life to take a reading from - white paintwork, white table cloth, that kind of thing. Finding a truly neutral grey in real life is extremely difficult and it's hard to tell just by looking at it.

To set a custom white balance, the card (or target area of the subject) only has to cover the centre circle, which the camera reads from.

That's the basics of exposure and will always get you a usable result, but if you really get into it the question of correct exposure or optimum exposure gets quite complicated and depends on your camera's sensor, the exact calibration, the subject, the result you want, and whether you're shooting for Raw or JPEG output.

The histogram will tell you exactly what's going on. That is generated off an actual image file, so it takes into acount all the variables, whereas any meter reading is only a guess based on a series of assumptions that may or may not be correct.
Click to expand...

Thanks Richard...thats really helpful! Regards to setting up a custom WB for my camera do I take this in AUTO rather than in Manual, TV or AP mode?
 
Vinnyvagus said:
Thanks Richard...thats really helpful! Regards to setting up a custom WB for my camera do I take this in AUTO rather than in Manual, TV or AP mode?
Click to expand...

You can use any mode for custom white balance, so long as the exposure is okay. So long as it's not too dark and posibly full of disruptive noise, or so bright that it's actually blown off the end of the histogram, it will be fine. You can also shoot the white balance target with any white balance set on the camera - it knows what's set and adjusts everything accordingly, working on the assumption that what you are pointing the camera at is neutral so it re-calibrates everything to that.

As an aside, I always have blinkies enables - the highlight over exposure warning that flashes back and white on the lCD to indicate areas that have blown to pure white. It's invaluable when you're trying to get the exposure absolutely optimum.

I should also point out that with various modes - Av, Tv, P, M etc - are just different ways of doing the same thing, according to convenience, the subject, preference etc. You can set whatever exposure level, or combination of settings, you like with any of them. By the same token, the different metering modes (evaluative, spot etc) are also just different ways of measuring the exposure, again according to subject, preference etc. I always use evaluative, which will always be close if not always perfect, and tweak according to the LCD/histogram/blinkies. Don't use spot unless you know exactly what you're doing.
 
once i take a grey reading can it be used for every photo shoot
 
derrycity said:
once i take a grey reading can it be used for every photo shoot
Click to expand...

Only if every photo shoot is done with exactly the same lighting.
 
The other thing to bare in mind with white balance is if you shoot raw you are able to adjust it afterwards.

Sounds good, but it's got me into the habit of more giving it any though, which is bad when I'm using my compact.
 
I'm just testing the grey card now at home but as I'm indoors I need to use the flash. Just now I took a photo of the grey card filling the VF and used the flash as well and then I set this as my custom WB. After reviewing the pictures I noticed they all look blue tint? Its late at night so I dont have any ambient light so I needed the flash to take the picture of the grey card to set my custom WB.

I also wanted to use the grey card to help set my exposure as I do in day light, but I cant do this with flash can I? i mean changing the Aperture and Speed does not show me in the VF the best exposure as it sits constantly to the left as its all dark without the flash going off! even though I am using the highest ISO and 1.8. Any help in using a grey card to set the exposure when using a flash as the dominant light source is appreciated....
 
Vinnyvagus said:
I'm just testing the grey card now at home but as I'm indoors I need to use the flash. Just now I took a photo of the grey card filling the VF and used the flash as well and then I set this as my custom WB. After reviewing the pictures I noticed they all look blue tint? Its late at night so I dont have any ambient light so I needed the flash to take the picture of the grey card to set my custom WB.

I also wanted to use the grey card to help set my exposure as I do in day light, but I cant do this with flash can I? i mean changing the Aperture and Speed does not show me in the VF the best exposure as it sits constantly to the left as its all dark without the flash going off! even though I am using the highest ISO and 1.8. Any help in using a grey card to set the exposure when using a flash as the dominant light source is appreciated....
Click to expand...

Regards the WB issue... are you using flash in a room that has tungsten lighting? This produces a slight orange light, which would mean your WB is off and slightly blue. Try doing the same with the lights off and see if this is still blue. The other option (which comes from film days) is to put CTO (orange) filter gel on your flash so the flash light is the same colour temp as the room lighting.

The exposure issue... you cant meter off something in the dark, agreed, but if you are using TTL there should be a pre-flash... if you want to set it up manually you can set up your shot in manual, and check the histogram, if exposed correctly the spike from the 18% grey will be in the middle of the histogram... if its too light/dark the histogram will be over to one side or the other!
 
Vinnyvagus said:
I'm just testing the grey card now at home but as I'm indoors I need to use the flash. Just now I took a photo of the grey card filling the VF and used the flash as well and then I set this as my custom WB. After reviewing the pictures I noticed they all look blue tint? Its late at night so I dont have any ambient light so I needed the flash to take the picture of the grey card to set my custom WB.

I also wanted to use the grey card to help set my exposure as I do in day light, but I cant do this with flash can I? i mean changing the Aperture and Speed does not show me in the VF the best exposure as it sits constantly to the left as its all dark without the flash going off! even though I am using the highest ISO and 1.8. Any help in using a grey card to set the exposure when using a flash as the dominant light source is appreciated....
Click to expand...

I don't think you are understanding everything correctly here. Either that, or I'm not understanding what you are trying to do.

You can only use a grey card to set either a custom white balance or exposure in the exact same conditions you intend to shoot in. And if you do it as instruced in the handbook, it will be very close to perfect (assuming your grey card is neutral - try a clean, pure white sheet of paper).

That's the first point. The second point is, if you are using flash, then the flash WB preset will set that directly for you. If you have a Canon gun (and most likely others too) it will select this automatically when set to AWB.

Likewise, if you are shooting in room light, then the tungsten WB preset will probably be pretty accurate, or the fluorescent one as appropriate.
 
Sorry if I didn't explain clear enough and I have no doubt I may be doing something incorrect. I'll start with the WB issue.

I was in my lounge and it was dark apart from a small lamp I have in my lounge. I used my Canon speedlight. I held the grey card in front of me and took the photo of it filling the whole VF. So I then went through and used this image to set my CWB. I then noticed when I pulled up the photo's on my PC after taking a number of shots that there is a tint of blue in all the pictures. I'm shooting in RAW so I could make the adjustments after so no real issue, but just wanted to know what I was doing wrong for the hint of blue when I set up the CWB the way I did (with the flash being the dominant light)

Onto exposure with the grey card.
In daylight I ask my subject to hold the card in front of their face and I zoom in so the VF was full with the grey card and I expose using that grey card so that using my Aperture, ISO and Speed made the exposure slider on zero. I then continue to take pictures and exposure does seem to be pretty good. Now last night in my conditions with little ambient light and using my flash I was wondering how I expose using the grey card the way I do during the day? Is there another way round this or is it completely different and in fact a grey card cant really be used in this kind of way when using a flash?

Hope this makes sense.
 
Vinnyvagus said:
Sorry if I didn't explain clear enough and I have no doubt I may be doing something incorrect. I'll start with the WB issue.

I was in my lounge and it was dark apart from a small lamp I have in my lounge. I used my Canon speedlight. I held the grey card in front of me and took the photo of it filling the whole VF. So I then went through and used this image to set my CWB. I then noticed when I pulled up the photo's on my PC after taking a number of shots that there is a tint of blue in all the pictures. I'm shooting in RAW so I could make the adjustments after so no real issue, but just wanted to know what I was doing wrong for the hint of blue when I set up the CWB the way I did (with the flash being the dominant light)

Onto exposure with the grey card.
In daylight I ask my subject to hold the card in front of their face and I zoom in so the VF was full with the grey card and I expose using that grey card so that using my Aperture, ISO and Speed made the exposure slider on zero. I then continue to take pictures and exposure does seem to be pretty good. Now last night in my conditions with little ambient light and using my flash I was wondering how I expose using the grey card the way I do during the day? Is there another way round this or is it completely different and in fact a grey card cant really be used in this kind of way when using a flash?

Hope this makes sense.
Click to expand...

It sounds like you're doing things right.

On the white balance, the blue tint could be because your grey card isn't quite neutral grey or the reading has become contaminated with ambient light. If you were inadvertantly using a long shutter speed on one of the auto modes, that's quite likely.

How does the grey card balance compare with the flash presetting? And was it really blue, or did it just look like that compared with the colour of the ambient-lit background? Technically 'correct' white balance often looks wrong especially in artificial light when a little warmth actually looks more natural.

On the exposure issue, you can use a grey card with flash in just the same way as in daylight, but you must be very carfeul to angle the card to avoid reflections. If you are firing a flash gun directly at it, the exposure could be way out.
 
You must log in or register to reply here.
Back
Top