question on exposure

[mdmedicgod]

Recently, I was asked to do a couple very informal headshots. The images were sharp. The person was happy. However, I used very crude lighting. I tried diffrent combos of on camera flash witch triggered my 420 with a shoot through umbrella etc etc... I used seemless paper. Slate grey. Some images the back ground was grey, and some it was a tan color. The final image that the person chose was the one with the tan background. My questiong is why did my grey back ground turn tan. FYI the final image was done only the 420 mounted on the camera..

[mickle]

Any chance you could post an example shot?

[kawter2]

this is most likely a White Ballance issue. The camera was probably fighting the blue cast that the strobes were putting out, thus making a Warmer WB.


W/O an example that is as good as i can get ;)

[mdmedicgod]

I will try to get an example. As soon as I can.

[PhotosGuy]

Auto Wb or Custom? If it was Auto, take a look at the "Gray card: Why your meter may be lying to you!" post here:
http://photography-on-the.net/forum/showthread.php?t=52418
At the bottom of the 2nd pic, "Finally, notice that the very last exposure was of a gray card. Full auto WB didn’t do much good there, did it?" That gray card came out a tan color.

[mdmedicgod]

Here is an example....



http://img.photobucket.com/albums/v471/Skydogs/teacher2.jpg

Tv( Shutter Speed )
1/125
Av( Aperture Value )
1.8
Exposure Compensation
0
ISO Speed
200
Image Size
2043x2736
Flash
On

[PhotosGuy]

So, what was the WB setting?

[mdmedicgod]

If I had to guess, cause I honestly doen't remeber. It was either AWB, or The preset wb setting for flash.

[PhotosGuy]

I tried diffrent combos... I suggest you use custom WB each time you change your lighting then.

[robertwgross]

It appears that you are not using a background light. That's fine, if that is the effect you want.

Sometimes a photographer will set up main and fill lights, a hair light, and then a background light. That way, you can control each aspect of lighting independently.

---Bob Gross---

[chtgrubbs]

I would guess that the background has some tungsten lighting on it which is warming it up. If you are using any auto exposure setting, (Program, Aperture Priority, or Shutter Priority) then the camera will give you the correct exposure for the ambient light and match the strobe output to balance it. If the ambient light is tungsten then the color balance for the parts of the photo not lit by strobe will be much warmer. You could switch to manual and use a higher shutter to lessen or eliminate the effect of the ambient light. When using flash, the aperture controls the flash exposure and the shutter speed controls the ambient light exposure.

[mdmedicgod]

Thanks for the insight

[Moments]

Looks like a combination of ambient light on the background (F1.8 @ 1/125), and if AWB was used, it might have been reacting to the subjects blouse. AWB is not always the best to use, unless neutral colors are in the image.

[Merle]

One of the first keys to overcoming the problems you have stated is; you mention inconsistancy. I'm guessing you have your camera set on an auto. mode and are using AWB. With different light scources on your subject your camera has got to make setting decisions each time you press the shutter release. Set your camera and flash on manual and do a custom white balance and your shooting will become consistant.;) :) :D


God's blessings on your household,
Merle

PS. Learn to use your cameras histogram this will insure your getting the exposures correct.