Gray cards

[Sole Shooter]

Just finished reading "understanding exposure" so, just curious how many people use gray cards?

[nqjudo]

Good book. I have a gray card in my bag that I have used on occasion. The WB settings on the camera do extremely well for most lighting so I only pull the card out if I want the final WB in the shot to be exactly representative of the scene. Incidentally, my gray card is not actually a card. It's a cleaning cloth that is 18% gray. It is called a 'spudz'. The dual function and compact form make it a great addition to a gear bag. I never use the card for exposure.

[griptape]

Good book. I have a gray card in my bag that I have used on occasion. The WB settings on the camera do extremely well for most lighting so I only pull the card out if I want the final WB in the shot to be exactly representative of the scene. Incidentally, my gray card is not actually a card. It's a cleaning cloth that is 18% gray. It is called a 'spudz'. The dual function and compact form make it a great addition to a gear bag. I never use the card for exposure.

Gray cards aren't so much for white balance as for exposure. As your mid tones in a scene should be 18% gray to avoid blown highlights and shadows that are too dark.

[nqjudo]

Gray cards aren't so much for white balance as for exposure. As your mid tones in a scene should be 18% gray to avoid blown highlights and shadows that are too dark.

I strongly disagree. A gray card is the best thing to use for WB. When you do a custom WB, you are calibrating for the white and not to it. You are taking a recording of reflected color temperature, not the surface color. A gray card has tonally neutral RGB values of 127/127/127 so this surface represents a perfect tonally neutral surface to take a reading from. If you take any white surface, the chances are that it's not truly white (RGB values of 255/255/255). White paint, paper, etc. contain all sorts of dyes, bleaches and other stuff that gives them a RGB values different than that of pure white. The result more often than not with a white surface is that you are taking a reading of a tonally unbalanced surface and getting WB reading that is not true to the scene.

Regarding mid tones, having them 18% gray has little to do with avoiding dark shadows and blown hi-lites. Even if your mid tones are 18% gray, this means nothing if your composition contains a dynamic range that is outside of your camera's ability to record it. A gray card can be a great help in difficult exposure situations like outdoors in snow but for the most part it's not at all necessary. Exposure has the benefit of being much more flexible and subjective than WB does - especially true if you are recording your shots in Jpeg.

You'll see pros at a wedding take WB readings off a gray card - never the dress.

[Sole Shooter]

Not to be arguementative or anything, but, according to Bryan the gray card is used to meter bright and dark subjects for a correct exposure. At least that seems to be the primary reason, now if getting WB settings can be done too, then hey that's icing on the cake.

[Rooz]

i always found that a bit odd for bryan to say that and never really quite understood it. i always thought it was for WB aswell. :confused: i don;t use one so i don;t know how they work. i've never really found the need given the capability and flexibility of RAW.

[nqjudo]

Not to be arguementative or anything, but, according to Bryan the gray card is used to meter bright and dark subjects for a correct exposure. At least that seems to be the primary reason, now if getting WB settings can be done too, then hey that's icing on the cake.

No argument here at all. A rather constructive exchange I think. The book does indeed give the impression that the primary, if not sole reason for a gray card is for exposure. After all, that's the title and scope of the book. Seen in a larger context, a gray card is arguably more useful for WB than exposure. Well, that's my opinion anyway.

If you like Peterson's books, 'Beyond Portraiture' is a very good read.

[JTL]

Just finished reading "understanding exposure" so, just curious how many people use gray cards?I never leave home without one, although it only gets used in about 10% of my shots...mostly when shooting with available light indoors...

[SpecialK]

I thought the book was a bit over-rated, and Peterson's phrases a little odd and confusing sometimes. Good photos though.

But on the topic, gray is an excellent tone to judge color casts. When I made color prints years ago. it was easy to see the "color" in gray.

I don't own a gray card anymore, and never do a WB. RAW lets me not worry so much about WB, and once I learned how to compare the LCD image to my monitor image, exposure is easy enough to check when shooting for the most part.

[nqjudo]

I thought the book was a bit over-rated, and Peterson's phrases a little odd and confusing sometimes. Good photos though.

But on the topic, gray is an excellent tone to judge color casts. When I made color prints years ago. it was easy to see the "color" in gray.

I don't own a gray card anymore, and never do a WB. RAW lets me not worry so much about WB, and once I learned how to compare the LCD image to my monitor image, exposure is easy enough to check when shooting for the most part.

Did you read his book on digital photography? What a disaster!

[SpecialK]

Did you read his book on digital photography? What a disaster!

I did not, and I guess I will not :-)