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Cutom White Balance using Expodisc.
^ Custom White Balance. Anyone experienced with the Expodisc? Recently attempted a custom white balance using one, when the shot was taken the entire image had a Green tint, obviously it didn't work as expected but what's up with that? Sep 23 15 05:20 am Link 51 Imaging wrote: Wow. Could you be a little more vague? Explain in detail what you did. Were you at the subject's position and aiming the lens with the disc on it back at the main light source? Did you use the right exposure? Is the disc brand new? Is it an actual Expodisc from Expoimaging or a cheap knock off? Sep 23 15 05:43 am Link I have one that came with a used camera I purchased a few years ago. I only used it a few times, but it seemed to work as advertised. Make sure you are pointing it at your light source when you do your CWB. My preferred tool is the Colorchecker - http://xritephoto.com/colorchecker-passport-photo Sep 23 15 05:50 am Link I use my ExpoDisks (plural) all the time. (I have them in by bag and my studio). I meter my light from the subjects position, and set the camera 1 stop darker to avoid blowouts. WB is dead on right every single time. Sep 23 15 10:27 am Link The ExpoDisc, whether old or the new 2.0 version is very accurate for setting a custom white balance, even under tricky lighting that might not work well with a grey card. You just need an accurate exposure while pointing back towards the light from the position of the subject. Set that frame as the target and then remember to tell the camera you are using a custom white balance. I've never had a problem. As a follow up to another comment above the ColorChecker Passport is also excellent. I have both. Sep 23 15 01:06 pm Link 51 Imaging wrote: I used to have one until it was stolen with other stuff. Sep 23 15 02:25 pm Link Looks like everyone is pointing you in the right direction... Sep 23 15 02:27 pm Link i found expodisc (i had the warm one) hit or miss plus i kept leaving the camera in manual focus. next. on my new canon 6D i tweaked the auto-WB (added a lot of blue) so it started coming out the way i wanted. Sep 23 15 03:26 pm Link I did not find the Expodisc anywhere near as accurate as a ColorChecker. It's better than trying to eyeball your LCD screen, but since the ColorChecker isn't much more expensive or larger, and using it isn't much more complicated, I'd never use an Expodisc again. I got yellow tints with my Expodisc. Your mileage may vary - but even on their website(which isn't totally controllable) and their printed literature(which is), many of their 'corrected' images are yellow. Not as warm as with the 'warm' model, but definitely tinted. Some of their 'uncorrected' images are actually more neutral than their 'corrected' ones. I know people generally prefer a warm tint, and mentally we equate 'neutral' with 'cold.' And maybe the literature isn't printed well. But either way, not a good look. Something else to keep in mind: as it ages, it will begin to lose accuracy. ColorCheckers do that too. The white plastic in the Expodisc yellows over time, and the printing on the ColorChecker fades. If you're a smoker, and you smoke in the room with your camera gear(shame on you!), or you leave your camera bag near a radiator, it'll only take a year or two to get pretty far off. Ditto for working under tungsten lights or in bright sunlight a lot. If you do none of those things, you should get at least a few years out of it before it starts to give off odd readings. Aside from the odd readings that some people already report, that is. I realize I'm in the minority there. Sep 23 15 04:58 pm Link I've had great success with ExpoDisc, even shooting sports in crummy gyms and skating rinks. Normally I set the white balance with my 50mm and swap out lenses. That's just been my workflow. Sep 23 15 05:17 pm Link Christopher Hartman wrote: Yes, I set the WB then the exposure, which is backwards. Sep 23 15 05:41 pm Link ontherocks wrote: It renders WB a tad cool compared to using a gray card, but it's usually about 70-90% closer than AWB. Sometimes only a touch better. Sometimes very warm. Sep 26 15 02:27 am Link Dan Saul Knight Imagery wrote: I don't think I would say the grey card is always more accurate than an ExpoDisc since it depends on various factors; not least the spectral neutrality of the target grey card since the quality can vary significantly between different manufacturers. Exposure is also an important factor when setting an accurate White Balance and sometimes a custom WB is the only viable option under certain lighting conditions. Sep 26 15 04:52 am Link On a side note, if anyone uses ANY WB target that says it is neutral and you use correctly and can prove that it is not by testing it with other known neutral targets, by all means send it back and ask for a refund or a replacement. I would not keep my Expodisc if it were off. But since I used other targets like the Passport and the WhiBal that are known neutral tones to check for accuracy, I use it since those target read neutral with using a WB set by the Expodisc. Gray cards, that are sold as "gray cards" are exposure tools whose only claim is that they are 18% gray. They don't have to be neutral. And a lot or not. Some have a green cast. Some have blue cast. Some actually are neutral. And again, if the manufacturer does say their gray card can be used for WB but it isn't neutral, send it back. Sep 26 15 07:39 am Link |
