GretagMacbeth ColorChecker Mini Grey Balance

[russellsnr]

Hi, I want to use the Sekonic DTS software to calibrate my cameras to my L758 meter when it arrives.
I have the color-checker passport but not the new one that has a new Grey target next to the WB target, to buy just the Grey target is about £30 I think about $45 but I have another make of Grey 18% target made by EZY, the round one with the X in the middle, do you think there would be a great difference using this one to calibrate the meter?
Thank in advance
Russ

[xpatUSA]

Theoretically, Russell, there should no great difference. The proof would be if you put them in the same scene, lit equally, took one shot and then checked the resulting image to see how close the RGB's or HSB's are. If you are concerned just about the reflectance of the card then perhaps the brightness part of your editor's HSB color-picker is all you need to compare. The RGB's are perhaps less useful because, for each card, they would differ (R from G from B) depending on the lighting.

What do you think? Of course the mini-card has several grays on it, but the info for those is on the packet or easily found on the 'net.

[russellsnr]

Theoretically, Russell, there should no great difference. The proof would be if you put them in the same scene, lit equally, took one shot and then checked the resulting image to see how close the RGB's or HSB's are. If you are concerned just about the reflectance of the card then perhaps the brightness part of your editor's HSB color-picker is all you need to compare. The RGB's are perhaps less useful because, for each card, they would differ (R from G from B) depending on the lighting.

What do you think? Of course the mini-card has several grays on it, but the info for those is on the packet or easily found on the 'net.

Hi, Thanks for the reply. The new colorchecker passport has two large targets now on the back, one W/B and one 18% Grey
Going to have to do a search for the comparison between the Grey cards as no point to buy the target at $45 if the difference is negligible with the EZY one I already have.
Thanks again
Russ

[LocalHero1953]

A word of warning. I can't speak for the EZY grey card, but I bought the Digital Grey Kard that is sold cheaply on amazon. It gives a significantly different white balance reading to the white balance and grey targets on the X-rite Color Checker Passport. Since I paid a lot more for the latter, I am sure that is the correct one :-)
But the lesson for me is - not all white balance cards are equal.

[Colin Southern]

A word of warning. I can't speak for the EZY grey card, but I bought the Digital Grey Kard that is sold cheaply on amazon. It gives a significantly different white balance reading to the white balance and grey targets on the X-rite Color Checker Passport. Since I paid a lot more for the latter, I am sure that is the correct one :-)
But the lesson for me is - not all white balance cards are equal.

Just be aware that cards sold as "18% gray cards" are actually for setting exposure, not white balancing. For white balancing one needs a spectrally neutral card (the reflectance of which isn't particularly significant)

[Colin Southern]

Hi, I want to use the Sekonic DTS software to calibrate my cameras to my L758 meter when it arrives.

Hi Russell,

Trust me -- just give up now (I'm serious).

Unless they've changed it, to get best results you really need one of their 2 test targets (using a colour checker will be far less accurate), but even with it (a) it's nigh on impossible to go through all the settings for flash / incident at all the ISO settings (b) the results I got having faithfully followed the procedure several times on several occasions were grossly inaccurate, (c) in reality the standards that the light meter and camera are already calibrated to are more than adequate (d) the camera captures far more dynamic range than a monitor or print can display and (e) you'll still need to adjust exposure and shadows in post-production anyway to account for where the meter/camera puts a middle gray on the histogram compared to where it needs to be for an image not to look flat (typically at least a 1 stop difference).

Enjoy the meter, but forget about calibration. Take a day off and go do something enjoyable instead.

[LocalHero1953]

Yes, I agree 18% grey cards aren't suitable as white balance cards. The Digital Grey Kard is actually three cards: white, grey and black, and sold for white balancing. Unfortunately none of them are consistent with the CC Passport. My fault for going cheap.