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Photovision Target Question
Old 08-25-2007, 07:17 PM   #1 (permalink)
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RFS,

You're probably the best person to answer my question.

I used the target as shown below:



When I shot the target:

- 200 mm
- 1/125
- É4
- ISO 100
- flash off

I then set the white balance. More specifically, I shot the target, went to the back and selected the image (current image), set white balance, and then set the dial to correct symbol for custom white balance.

My next image has a green cast.



These were shot within two minutes of each other on a reasonably clear day.

Any idea where I went wrong?

Regards,
Kevin
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Last edited by Stecyk; 08-25-2007 at 07:43 PM..
 
Re: Photovision Target Question
Old 08-25-2007, 07:28 PM   #2 (permalink)
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You need to completely fill the frame with the target.
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Re: Photovision Target Question
Old 08-25-2007, 07:31 PM   #3 (permalink)
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Quote:
Originally Posted by Stecyk View Post
RFS,

You're probably the best person to answer my question.

I used the target as shown below:



When I shot the target:

- 200 mm
- 1/125
- É4
- ISO 100
- flash off

I then set the white balance. More specifically, I shot the target, went to the back and selected the image (current image), set white balance, and then set the dial to correct symbol for custom white balance.

My next image has a decided green cast.



These were shot within two minutes of each other on a reasonably clear day.

Any idea where I went wrong?

Regards,
Kevin
It may depend on the camera, but the gray part of the target must totally fill the center portion of the viewfinder. I never use the target the way you're showing it in the photo for WB settings. I fill the frame with the target (the whole viewfinder). This more or less guarantees that the gray part will completely cover the central metering circle. I also find that it is wise to have the proper exposure for the target. The shot you show is not properly exposed. Here is the histogram of your target



As you can see there are only two spikes, the third is missing. The basic way you use the target is first get the exposure zeroed in by getting three good spikes, and then use that final target shot for your CWB. In all cases, always fill the entire viewfinder with the target.

Cheers,
rfs
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Re: Photovision Target Question
Old 08-25-2007, 07:45 PM   #4 (permalink)
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Quote:
Originally Posted by RobArtLyn View Post
You need to completely fill the frame with the target.
Thank you!
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Re: Photovision Target Question
Old 08-25-2007, 07:55 PM   #5 (permalink)
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Quote:
Originally Posted by R_Fredrick_Smith View Post
It may depend on the camera, but the gray part of the target must totally fill the center portion of the viewfinder. I never use the target the way you're showing it in the photo for WB settings. I fill the frame with the target (the whole viewfinder). This more or less guarantees that the gray part will completely cover the central metering circle. I also find that it is wise to have the proper exposure for the target. The shot you show is not properly exposed. Here is the histogram of your target



As you can see there are only two spikes, the third is missing. The basic way you use the target is first get the exposure zeroed in by getting three good spikes, and then use that final target shot for your CWB. In all cases, always fill the entire viewfinder with the target.

Cheers,
rfs
Thank you RFS!

I am using a Canon 20D. I tend to use my Sekonic light meter for exposure setting. They (target and light meter methods) should agree, so I am sure what happened here.

Here's another shot taken within five minutes of the target shot. Same exposure settings. It does look a tad bright. In fact, in Photoshop, I would reduce the exposure by about 0.75 to 1 É stop. Still not sure what happened with the light meter.



Okay, so if I understand your steps correctly, get the histogram (exposure) set first, and then fill the frame (move closer if required) to set white balance.

Thank you very much for your assistance.

Here's the same picture again, with one less É stop of exposure and some color correction.





Best regards,
Kevin
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Last edited by Stecyk; 08-25-2007 at 08:49 PM..
 
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