5D MkII underexposes by 0.7stops by default!

[EdBray]

I've just taken some images with my 5D MkII and I have found that the meter is set to underexpose by 0.7 stop.

Took a shot of my grey card and this came up below halfway on the histogram, similarly when I took a shot of my white door in which I wanted to keep some detail it came out a light grey. Increasing the exposure by 0.7 stop improved the images no end.

Images posted have had absolutely no PP at all, straight jpgs out of the camera! All taken on 100mm Macro at about 2 mtr distance. (didn't want the mfd to increase the exposure)

Image 1, Grey card, directly as metered. (too dark)

http://i332.photobucket.com/albums/m338/EdBray/IMG_1086.jpghttp://i332.photobucket.com/albums/m338/EdBray/IMG_1986.jpg

Image 2, White Door, directly as metered (too dark)

http://i332.photobucket.com/albums/m338/EdBray/IMG_1087.jpghttp://i332.photobucket.com/albums/m338/EdBray/IMG_1987.jpg

Image 3, Grey Card, +1 exposure, (bit bright)

http://i332.photobucket.com/albums/m338/EdBray/IMG_1089.jpghttp://i332.photobucket.com/albums/m338/EdBray/IMG_1989.jpg

Image 4, White Door, +1 exposure, (bit bright but still retains detail)

http://i332.photobucket.com/albums/m338/EdBray/IMG_1088.jpghttp://i332.photobucket.com/albums/m338/EdBray/IMG_1988.jpg

[EdBray]

Image 5, Grey Card, +0.7 Exposure, Correctly exposed.

http://i332.photobucket.com/albums/m338/EdBray/IMG_1091.jpghttp://i332.photobucket.com/albums/m338/EdBray/IMG_1991.jpg

Image 6, White Door, +0.7 Exposure, Correctly exposed.

http://i332.photobucket.com/albums/m338/EdBray/IMG_1090.jpghttp://i332.photobucket.com/albums/m338/EdBray/IMG_1990.jpg

[JeffreyG]

This kind of concern is common, I can recall a bit of a hubbub about the metering on the 40D when it was released. The answer is pretty simple though. If you plan to use the camera meter, then you simply need to remember that +2/3 EC is the -zero- setting for exposure compensation.

I tend to not use the meter in my 5D all that often, but when I do shoot in Av mode I almost always use +2/3 stop as the default starting position. Perhaps the 5D and 5D2 meter similarly.

[tzalman]

Your camera is metering just the way it should. Read these:
http://www.bythom.com/graycards.htm
http://doug.kerr.home.att.net/pumpkin/Scene_Reflectance.pdf

[iacas]

Nothing looks wrong to me. How often do you go out and shoot pictures of grey cards anyway?

Every camera Canon releases I think I've seen people say "it under-exposes 2/3." They don't...

[Wilt]

Regarding Image 1...An 18% gray card should photograph to 18% gray, not to 50% gray! I see no issue here. Image 5 is just plain 'not right'

[EdBray]

Regarding Image 1...An 18% gray card should photograph to 18% gray, not to 50% gray! I see no issue here.

Lol! an 18% grey is mid range.

[Wilt]

Lol! an 18% grey is mid range.


This is 'mid-range' or 128-128-128 for R-G-B values on a 256 level scale (what your histogram portrays, and what would be at the center of the histogram!)...

http://i69.photobucket.com/albums/i63/wiltonw/RGB_128.jpg

The 18% is not 'mid-range' of the digital scale, it is the legendary 'average of the brightnesses of a typical scene' which was experimentally determined by Kodak engineers in the days of film. And 18% is not the brightness levels which is 'what meters are calibrated to'...the reflectance standard to which reflected light meters are calibrated to is about 12-13% gray.

[Wilt]

If you shot an accurate representation of the GretagMacbeth Color Checker, the white square has R-G-B values about 245 (+-7), the black square has values about 50, and the middle gray (bottom row, square 4) is 128. Shoot that and see what you get.

http://i69.photobucket.com/albums/i63/wiltonw/Spot-1.jpg