Grey card help...

Chris Perry

Chris Perry

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Chris
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Hi Peeps, just a quick question, I’m a bit confused with using a grey card in a studio, if I was taking a meter reading from the camera, am I right in saying; you have to zoom in to the card while it is being held by the subject and then, half depress the shutter release and then press the AE-L/AF-L button and that will lock the exposure at 18% grey ?? I would really like some help on this subject, so if you can help it would be much appreciated.

Cheers
Chris.
 
I have not used one yet but thought the grey card was for setting your custom white balance and then referencing this for each shot in the same light?
 
bootie said:
I have not used one yet but thought the grey card was for setting your custom white balance and then referencing this for each shot in the same light?
Click to expand...

It's original purpose was for setting exposure - been in use in that role for decades.

They are OK for setting white balance, but a white card would work better.
 
As far as I've always understood it the grey card can be used for white balance or for exposure, you can use the AE-L or AF-L button or just take note of the suggested exposure settings and set the shot up (assuming that you are using a consistent light source of course!). Happy to be corrected by those more in the know though!

K.
 
Chris Perry said:
Hi Peeps, just a quick question, I’m a bit confused with using a grey card in a studio, if I was taking a meter reading from the camera, am I right in saying; you have to zoom in to the card while it is being held by the subject and then, half depress the shutter release and then press the AE-L/AF-L button and that will lock the exposure at 18% grey ?? I would really like some help on this subject, so if you can help it would be much appreciated.

Cheers
Chris.
Click to expand...

Yes, you need to fill the fram with the grey card, so that the meter is not influenced by any surroundings.

The meter will always interpret everything as 18% grey, in the hope that it is an average scene that will quite closely equate to 18% grey anyway. But if you want to make sure that 18% grey sits on the histogram at exactly the right point, you need to use a guaranteed 18% grey subject, ie the card. In effect it is the same as an incident light meter reading, such as you would do with an invercone on a hand-held meter.

kh_42 said:
As far as I've always understood it the grey card can be used for white balance or for exposure, you can use the AE-L or AF-L button or just take note of the suggested exposure settings and set the shot up (assuming that you are using a consistent light source of course!). Happy to be corrected by those more in the know though!

K.
Click to expand...

Yes, that's right. You can use any subject you like for exposure meter reading, so long as it is a known reflectance and you make the appropriate compensation adjustment. 18% grey just saves you the trouble of making any such adjustment and you just take the meter reading and set it directly.

You can also use any neutral subject for white balance, that is equal quantities of red, green and blue. That can be grey, white (so long as it is not blown to over-exposure), light grey, dark grey (so long as it's not under-exposed and awash with noise) whatever - so long as it is neutral.
 
Hey thanks Richard, i understand it better now, i take it then that you can't use one when using studio flash, as it's only possible to get a meter reading in natural light, so flash metering can only be done with a light meter.
i hope i've got it right.

Chris
 
I use a grey card under flash conditions, but only as a reference point when I'm shooting fabrics. It's used only as a reference and is usually in the first shot . This way the correct colour can be ascertained and then all other shots referenced to that.

I don't use for Auto white balance. Set the camera to Flash or daylight ( whichever works best ) and use the grey card to get the image neutral.

As has been said any neutral card will do as long as it is Neutral and not too dark or light.
 
Chris Perry said:
Hey thanks Richard, i understand it better now, i take it then that you can't use one when using studio flash, as it's only possible to get a meter reading in natural light, so flash metering can only be done with a light meter.
i hope i've got it right.

Chris
Click to expand...

Not quite. You can use an 18% grey card to take a flash meter reading if you want - just switch the meter to reflected light reading (slide the invercone away) and point it at the grey card (or whatever else you want to meter off) just like normal.

The invercone is just like a built-in 18% grey card, if that makes any sense. It absorbs the right amount of light, instead of reflecting it. Same result, but much more convenient.
 
That's pretty similar to what I do...

In a photo situation I get the subjects to hold a WB card while I set up for exposure, etc.

_MG_2824_WB.jpg


Then after the shoot I run the raw files through Lightroom and use the WB card from the first shots as a reference, then copy the values to the other pictures.

Saves messing about at the location... a quick "hold this while I set up" followed by a quick few post-processing clicks and the job is done :thumbs:
 
Beware that if you zoom in on the grey card at a wide aperture with a lens without a constant aperture, the lens will stop down a bit and then open up when you revert to a shorter focal length.

There's no need to fill the frame if you set the camera to spot meter.
 
MC_Stoo said:
That's pretty similar to what I do...

In a photo situation I get the subjects to hold a WB card while I set up for exposure, etc.

<snip>

Then after the shoot I run the raw files through Lightroom and use the WB card from the first shots as a reference, then copy the values to the other pictures.

Saves messing about at the location... a quick "hold this while I set up" followed by a quick few post-processing clicks and the job is done :thumbs:
Click to expand...

That's for white balance, not exposure.

And welcome to TP :)
 
HoppyUK said:
That's for white balance, not exposure.

And welcome to TP :)
Click to expand...

I agree entirely with what you say... I probably haven't phrased myself clearly in my post...

My radio triggers do not transmit ETTL information so I have the flashguns and camera set on manual (hence my reference to setting exposure at the same time as setting the WB). The WB card just happens to be in the shots as I do it :lol:

Thankyou for your welcome... this seems like a friendly forum :)
 
MC_Stoo said:
I agree entirely with what you say... I probably haven't phrased myself clearly in my post...

My radio triggers do not transmit ETTL information so I have the flashguns and camera set on manual (hence my reference to setting exposure at the same time as setting the WB). The WB card just happens to be in the shots as I do it :lol:

Thankyou for your welcome... this seems like a friendly forum :)
Click to expand...

It is a friendly place. One thing I think the mods take pride in :)
 
to meter read you need to use a meter
camera on M
transfer readings and adjust accordingly to what f no you shoot at
 
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