1ds AWB, Digital Calib. Target and Exposure

Greetings all,

About eight months go i got a 1ds mark ll and have done nothing but shoot in raw in evaluative mode and correct my own prints.

Now I've got a school portrait gig where the lab only wants JPEG with custom white balance. They get thousands of files and want as nearly a "perfect" file they can get. I decided to use the one shot Digital Calibration Target because the lab wants as nearly a technically perfect file as possible.Since its coming up in a couple of days i wanted to post....

1) Is the three strip black, gray, white target better to use, as the inventor, Mr. Pierce (sic?) claims, than using just white? Or at this point should I just use white and hope for the best?

2) I didn't quite get Mr. Pierce's instruction on the accompanying DVD on setting the best histogram... The histogram should show 3 evenly spaced spikes to indicate perfect exposure, right? I should increase/decrease over optimum exposure indicated in the viewfinder until I get those 3 evenly placed spikes in the histo? Don't quite have the faith in overexposing (with ttl metering) on the card to get a good histogram...advice appreciated...

3) Once AWB is set, it stays in the camera even when you change cards and you are
always shooting in AWB thereafter, right?

Finally, these are little kids, many dark complected but wearing stark white dresses. With evaluative metering, I noticed faces were under exposed and dresses were good. Has anyone used spot metering on faces with AF, holding the shutter down halfway, recomposing and shooting?

Thanks so much for your comments...

Trax

If you're happy with a RAW based workflow, why not continue with a RAW based workflow? You can always generate the JPEGs as a batch from the RAW files. However, depending on the volume of files, in-camera JPEGs may save you a lot of time for this sort of job.


You seem to be mixing up auto white balance and custom white balance. For custom white balance, you need to shoot a neutral reference that fills a certain proportion of the viewfinder (check your manual), then set that shot as your custom white balance reference. Finally, you set the camera to use the custom white balance.


It's almost impossible to comment on the exposure and metering side of things because you give no information about the lighting in use. Are you using ambient light, E-TTL fill flash, E-TTL main flash or studio lighting? If using Speedlites, how many Speedlites are you using and where are they placed?

Spot metering skin is tricky and probably the wrong approach here, because the correction you have to apply depends on skin tone (African skin is much darker than Caucasian skin).

David

Thanks David...

Yes, I'm shooting four poses of 40-60 children and shooting raw would be out of the questions. Besides, the lab wants as close to a technically perfect file as possible, hence the custom white balance request. They are processing thousands of these types of files.

Shooting a card with black-gray-white stripes was suggested as superior to only a neutral white card. I'm using Ed Pierce's Digital Calibration Target. As I understand it, you are supposed to see 3 evenly spaced spikes or peaks in the monitor after shooting the reference card. The question is:

do i continue to continue to change exposure of the reference card until I see get perfectly evenly spaced peaks?

I'm using continuous even lighting which I prefer because we're always changing props
and I can see the shadows with that. Yes, when little black girls wear pure white, it seems evaluative mode leans toward the white. That's why I was thinking about spot...

Any suggestions appreciated...cheers..​.Trax

If you're in control of the lighting (sounds like you're using hot lights), use M mode. If you have a light meter use that (in incident mode). If not, then an 18% grey card should fall right in the middle of the histogram - one way to arrange that is to spot meter the grey, assuming that it really is a mid grey.

Once you have the aperture / shutter speed / ISO set, then if the lighting doesn't change, it should remain correct throughout the entire shoot. Don't keep fighting the metering - meter once with a reference and leave it alone. The Custom White Balance only needs doing once, too.

David

Thanks yet again David.

No, I am not using an external light meter. So as I understand it, I should spot meter on
the gray, use that as my AWB reference photo and shoot in AWB. The lights do not change, but my position does throughout the day, thus changing the exposure settings. Again, obvious question, should I do another AWB reference picture from my new position--technically?

cheers...trax

It's unlikely that the white balance will move very much as you move around the set. The exposure sounds as if it may move a little.

If you have a backdrop that's not too patterned, I'd spot meter off that once you've set the exposure using the reference card, so that you know where the meter 'needle' should fall, then you can adjust your shutter speed as necessary.

If you don't have a backdrop that's easy to meter off, you may either need to keep an eye on the histogram, or occasionally shoot a grey card.


Has anyone else got any ideas as to how to handle this shoot?

David

Processing and converting 160 to 240 RAW images is not out of the question unless your deadline is measured in minutes. It's possible to spend less than one minute per image in post-processing and make a world of difference, and since you seem a bit unsure of your metering and white balance skills, it would be good insurance.

Beyond that, I concur with what David suggests. Check your metering occasionally with a gray card, especially when the distance from light to subjects changes.

By the way AWB stands for "auto white balance" which is not what you want, especially with continuous lights. Custom white balance will be necessary.

It's unlikely that the white balance will move very much as you move around the set. The exposure sounds as if it may move a little.

If you have a backdrop that's not too patterned, I'd spot meter off that once you've set the exposure using the reference card, so that you know where the meter 'needle' should fall, then you can adjust your shutter speed as necessary.

If you don't have a backdrop that's easy to meter off, you may either need to keep an eye on the histogram, or occasionally shoot a grey card.

David