how is gray card used
Jun 1, 2012 20:58:14 #
Jun 1, 2012 21:08:25 #
For setting the white balance in post, place it in the scene and take a test shot. Using the 'eyedropper" type tool in the editing software, click on the grey card to set the WB.
For setting a custom white balance in the camera, fill the frame with the card, focus as best as you can (use manual focus) and take a shot. Nikons give you a menu selection for this (making a reference photo); I'm not sure how other cameras do it. The reason the autofocus won't work is you are either too close, or there is not enough contrast for the AF to capture.
For setting exposure, you meter off the card that's been angled half-way between the camera lens and the light source. This is where the "18% grey" comes into play. It doesn't mean it's 18% between black & white, but refers to the reflectivity.
For setting a custom white balance in the camera, fill the frame with the card, focus as best as you can (use manual focus) and take a shot. Nikons give you a menu selection for this (making a reference photo); I'm not sure how other cameras do it. The reason the autofocus won't work is you are either too close, or there is not enough contrast for the AF to capture.
For setting exposure, you meter off the card that's been angled half-way between the camera lens and the light source. This is where the "18% grey" comes into play. It doesn't mean it's 18% between black & white, but refers to the reflectivity.
Jun 1, 2012 21:17:11 #
Thanks Snowbear. I will try your methods. I have a Canon 50D and was using Av mode. I haven't tried post yet, but is it your opinion that it's best to just do post gray card method?
Jun 1, 2012 21:24:13 #
So far, for me, the standard WB settings have worked fine. I shoot raw most of the time so I have to do some post processing anyway. If you are happy with your results, otherwise and don't do a lot of post, then try to set it in camera.
Jun 1, 2012 21:31:55 #
Jun 2, 2012 01:06:04 #
Actually with a Canon you don't need to fill the frame, you only need to fill the circle that is around the center focus square. That's for White Balance. You don't need to have it in focus.
Jun 2, 2012 01:12:15 #
This is where in PP when I am trying to add "snap" to a photo I add +18% contrast - most usually that works out well. I did use a gray card sometimes long ago with film SLRs.
Guypix wrote:
Thanks Snowbear. I will try your methods. I have a Canon 50D and was using Av mode. I haven't tried post yet, but is it your opinion that it's best to just do post gray card method?
Jun 2, 2012 02:12:52 #
(I'm sure there are many others)
Technical http://thediscerningphotographer.com/2009/08/26/using-a-gray-card-for-exposure-in-photography/
Easier http://www.rmimaging.com/information/gray_card_use.html
Technical http://thediscerningphotographer.com/2009/08/26/using-a-gray-card-for-exposure-in-photography/
Easier http://www.rmimaging.com/information/gray_card_use.html
Jun 2, 2012 08:07:40 #
There are targets out there that allow AF to work. Gray cards are cheaper, just use manual focus. Using custom white balance feature gets my vote.
Jun 2, 2012 08:53:52 #
ziggykor wrote:
Neat. Learning every day.Actually with a Canon you don't need to fill the frame, you only need to fill the circle that is around the center focus square. That's for White Balance. You don't need to have it in focus.
Jun 2, 2012 09:00:39 #
Has any one tried the Whibal white balance card? I have and it works well in camera raw for batch correcting photos.
Jun 2, 2012 09:37:35 #
DRC56
Loc: Sartell, MN
I use the gray card to meter for proper exposure, I place it in the same light as the subject, fill the frame and meter, then I either "meter lock" or use manual exposure.
Jun 2, 2012 11:32:17 #
Guypix wrote:
I tried to focus but camera would not take the photo.
comment withdrawn
Jun 2, 2012 18:33:18 #
Guypix wrote:
Thanks Snowbear. I will try your methods. I have a Canon 50D and was using Av mode. I haven't tried post yet, but is it your opinion that it's best to just do post gray card method?
Grey cards have been around a long time. It is standard practice to calibrate reflectance light meters, both in and out of the camera type, to give accurate meter readings at 18% reflectance. This was used because it has been thought (under some controversy) that the average scene has 18% reflectance. However as hundreds of photographers have observed, there is no "average" scene. It is important when using a gray card that your card has the same light falling on it as your subject.
Jun 2, 2012 18:47:44 #
Yes - I would hold the gray card next to the subject - take my reading and set the camera - then click the shutter.
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