Glad to. This has been bantied about the internet for some time. First let's consider what middle gray is. Is it an abitrary shade of gray? No it is the average scene in mid-northern latitudes in the morning or afternoon on a sunny summer day. That happens to be about 18% gray. That is why it was selected. Grass, trees, etc. have about that reflectance.
Now about meters and 18% gray. I use a Sekonic incident meter, when I read on the internet that it measured 12% instead of 18% I wrote Sekonic, they rightly didn't bother to answer. Why? Because when I checked it against a gray card it got exactly the same reading in both modes. So it is calibrated at 18%. Shots on slide film confirmed that reading. Why this internet myth that meters are calibrated at 12%? Well the first thing I notice is they always tell you to hold the gray card at 45%. That is wrong, and will give you a wrong reading. You are supposed to hold the card vertically, and point the meter at it. When you hold the card at 45% you get a higher reading, and when they compare that to an incident reading or properly processed slow slide film it seems to be off. The other thing is that Sunny 16 rule. 90% of the time it will give you one or two stops of underexposure, because the light is usually less than that due to smog, haze, dark surroundings. So it is not an accurate way to check your meter. I often like to challenge someone to see which of us get a closer estimate using it. I use sunny 11 compensated by my estimate of the surroundings and the haze level, almost always I am too high by a 1/2 stop or so, but mosty well within the film latitute that is much closer then an unthinking sunny 16 estimate. Just because everybody says it is so, don't make it true, especially on the internet. Don't take my word, go out and experiment a bit. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto ----- Original Message ----- From: "Feroze Kistan" <[EMAIL PROTECTED]> > I don't know enough about grey cards to comment but I did find this site > when trying to research it: > www.camerahobby.com/E-Book/EBook-Metering_Chapter3.htm. At the bootom of his > site he makes the comment that grey cards are actually 1/2 stop off (12-15% > grey). Anyone care to comment. > >
