Sekonic 758DR Compensation

[cortes]

I was testing with my new Eclipse umbrellas when I noticed I was under exposing my shots. I took a reading of the main with my Sekonic 758DR and got f/8.0 at 1/250. There may have been a tenth or two as well. I noticed the histogram was well off the right side. I brought it into ACR and add .7 to the exposure to bring the histogram all the way to the right. The attached photo is the result. I did other other shots with a .7 compensation added into the 758 and they filled the histogram. Is .7 a lot of compensation to have to add? I made sure the ISO matched on the 758 and the camera (D3) and that there was not any exposure compensation set on the camera.

Other the other hand, do you think the shot now looks overexposed?

[SYS]

When I first got my 758DR about two years ago, I remember calibrating it to my then 20D with the exposure compensation adjusted in the lightmeter with either .6 or .7.
I was a bit surprised by that amount of compensation...

[TMR Design]

Hi Curt,

Even though .6 or .7 seems like a lot, it's very common to apply 2/3 of a stop compensation or CAL adjustment. If you're getting accurate exposures then that's the number. No reason to suspect anything is wrong. Make sure that when you check exposure of a subject that you're checking the facial mask histogram and not just the overall image. The histogram for a properly exposed frame and a properly exposed subject can be vastly different.

[cortes]

Make sure that when you check exposure of a subject that you're checking the facial mask histogram and not just the overall image. The histogram for a properly exposed frame and a properly exposed subject can be vastly different.

Thanks Robert

I was thinking about that after I made the post. I have the Sekonic calibration target. To eliminate some of the variables, I'll shoot it filling the frame. Would I be correct in assuming that spike in the histogram should be in the center of a proper exposure?

You gave me a lot of help building a profile (I've forgotten the correct name for it) of my camera about a year ago that I loaded to the 758. Would it have any impact on the compensation? I created it using a couple of halogen desk lamps, so conditions were less than ideal. One more reason to spring for some Elinchrom's.

[TMR Design]

Hi Curt

If you're creating a custom profile the the calibration is part of it and the calibration is stored within the profile and there is an independent calibration value for each ISO and mode.

When you set a global CAL value you only have one for ambient and one for flash.

When you set the offset with the ADJ value then there's only global value for the whole meter.

[cortes]

I have the Sekonic calibration target. To eliminate some of the variables, I'll shoot it filling the frame.

I shot the card today starting at .7 adjustment in the 758DR. There was a nice tight spike about 3/4 the way to the right. I started reducing the adjustment to get the spike to the center. By the time it was there, the adjustment was zero. I guess I'll have to rethink my filling the histogram goal. It probably make sense for landscapes but not portraits on a gray background.

[TMR Design]

When shooting the target and performing a calibration, the only thing you're concerned with is having the 18% gray spike dead center. You shouldn't have other information in the histogram and the spike my be smack in the middle.