18% grey card

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DaveKing

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I am thinking about buying a grey card to help with exposure and getting my white balance right in camera. I mainly do travel photography and 'snaps' when out and about, so I'd anticipate using it to set up exposure & WB manually before shooting for an hour or two.

Am I better getting off a small one on a lanyard like this:
http://www.ebay.co.uk/itm/7dayshop-...531?pt=LH_DefaultDomain_3&hash=item4165674b43

Or will it be too small and I am better off getting a more traditional one that is (say) 12"? But my question is how small do these collapse? Can you get them in the front pocket of most camera bags?

Cheers!
 
Small ones are useless IMHO. Lastolite do a good range of large fold-up jobbies.

Be aware that grey cards intened for exposure measurement are not always dead neutral, though most should be. White is arguably better for WB anyway (less danger of noise) and white paper is as good as anything, so long as you don't blow it.

Also, your camera is probably not calibrated to 18% grey and is more likely 15% or even 12%, so you could get slight under exposure if you follow it exactly.
 
HoppyUK said:
Small ones are useless IMHO. Lastolite do a good range of large fold-up jobbies.

Be aware that grey cards intened for exposure measurement are not always dead neutral, though most should be. White is arguably better for WB anyway (less danger of noise) and white paper is as good as anything, so long as you don't blow it.

Also, your camera is probably not calibrated to 18% grey and is more likely 15% or even 12%, so you could get slight under exposure if you follow it exactly.
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Thanks HoppyUK. From looking around there are 12% and 15% cards, would one of these be better for a DSLR? Or am I better off getting an 18% and then tweeking the exposure (+/-) to suit by looking at the histogram?
 
markmullen said:
Although it is expensive I use Colorchecker Passport for stuff where getting a bang-on white balance is critical.
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That looks great, but a little over my budget at the moment. If I was getting paid to use it, it would be a different story all together!!
 
DaveKing said:
Thanks HoppyUK. From looking around there are 12% and 15% cards, would one of these be better for a DSLR? Or am I better off getting an 18% and then tweeking the exposure (+/-) to suit by looking at the histogram?
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Doesn't really matter, so long as you know what it is. The real point is it's a constant reference.

Shoot a picture of it with the camera in an auto mode, card filling the frame, then check the histogram. When I do that with my Canon, I get a spike about 0.3 of a stop to the left of centre, suggesting something like a 15% calibration.

But if you're going to this amount of trouble, presumably you know all about Expose To The Right (of the histogram) technique? In which case, you would disregard mid-grey and go for 'optimum' exposure rather than technically correct exposure, and adjust in post processing.

That's a whole other subject though ;)
 
Brilliant, thank you. I am trying not to have to tweek too much using Lightroom, which is my reason for getting this. If I can get it right in camera there will be less noise too which I find important when using my 450D. I think I will get the Lastolite Ezybalance grey card and look to tweek the exposure in camera to suit.

Thanks again!
 
The only problem with shooting a white piece of paper (assuming you don't overexpose any channel) is that there are various shades of white.....
 
HoppyUK said:
Shoot a picture of it with the camera in an auto mode, card filling the frame, then check the histogram. When I do that with my Canon, I get a spike about 0.3 of a stop to the left of centre, suggesting something like a 15% calibration.
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If you actually read the instructions in an R-27 set of Kodak grey cards, it specifically says to add on a 1/3rd of a stop for all subjects of normal reflectiveness when metering off it.
 
arad85 said:
The only problem with shooting a white piece of paper (assuming you don't overexpose any channel) is that there are various shades of white.....
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Yes, they do vary a bit, but they'll get you very close. Some of the grey cards I have tried, claimed as neutral, vary by a similar amount too.

As a comment, we are quite tolerant of white balance and sometimes technically incorrect white balance looks better than strictly accurate. Obvious examples might be a sunset, or candle light or bonfire light. Personally, I always adjust final white balance by eye rather than following a grey/white card religiously. What is absolutely critical is to get any series of images taken of the same subject exactly the same. Any shifts there in a side by side comparison will show up immediately.
 
s162216 said:
If you actually read the instructions in an R-27 set of Kodak grey cards, it specifically says to add on a 1/3rd of a stop for all subjects of normal reflectiveness when metering off it.
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That's interesting Samuel. It tallies with my own findings, but the Kodak R-27 cards I have make no reference to anything except 18% grey.

I'd be interested to read what is actually says about that, do you have a link or reference? Thanks.
 
The instructions just literally say to add on 1/3rd of a stop for subjects of normal reflectiveness, I can't find an electronic copy of the instructions anywhere at the moment and Kodak Publication no. R-27 which would give the same information doesn't seem to be on their website anymore. I'll have a go at finding my physical copy of the instructions later, I randomly found them a couple of months ago so I should be able to track them down.
 
s162216 said:
The instructions just literally say to add on 1/3rd of a stop for subjects of normal reflectiveness, I can't find an electronic copy of the instructions anywhere at the moment and Kodak Publication no. R-27 which would give the same information doesn't seem to be on their website anymore. I'll have a go at finding my physical copy of the instructions later, I randomly found them a couple of months ago so I should be able to track them down.
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No worries Samuel, thanks. The small print of the instructions does say something along those lines.

Add 1/2 stop for normal subjects, minus 1/2 stop for very light subjects, and plus 1-1.5 for dark subjects.

I was particularly interested in a reference to 15% calibration, as camera makers never quote things like this :)
 
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