Why Use a Color Chart?

Just do know it expires, it's a consumable. Must be completely sealed in dark if you want to keep as long as possible the color accuracy. What @shian said.

@shian yup x2

Davinci Resolve has built-in correction tools which, with properly exposed and already reasonably closely balanced footage (as Caveport said) automatically do the advanced corrections required by the Macbeth charts (including the x-rite, sekonic, and other "colour checkers" and the passport series). The article is right in a the still photography version of those tools is a bit out of gamut for REC709, but you'll still get a damn close match that is quite useful. I certainly see the point in using the product advertised in that article, especially if you want to manually match your colours, but there's absolutely nothing wrong with using the Colour Checker Passport to get you at a solid base. I then use FilmConvert to take it to the basic film look I want, then apply my style grade on top of that. Remember: correction LUTs before conversion LUTs before style LUTs.

I use one with DaVinci Resolve and it works well. Keep in mind that they are not designed to work with poorly white balanced footage. The linked article is promoting an alternative product! ;-)

johanson - Thanks for the link to the MBR Color Corrector plugin. Looks very interesting. I have used profiles for film scanners, and found them very useful. They not only speed up the work flow, but insure far more accurate color adjustments with less degradation to the image.

So, x-rite color checker passport bundled software does not allow for creation of an icc/icm color profiles. One can use a target that comes with color checker to create an icc profile with a professional color profiling solutions (Ks of $). What color checker does is to generate a DNG color profile which maybe applied only to RAW or DNG files. So this makes it unusable for video even if you take Render to frames>Tiff or Jpeg through camera raw>open tiff/jpeg sequence in AE.

I like it for the b option, multi-cams calibrating prior to color correction.
Another option i see is lens matching. My leica the 90 is 100°K warmer and the 135 110°K warmer than my 28 and 50.
I will try to get my hands on a canon to see if get them to match.

Let me to point out that a capture device icc color profile is nothing else but a LUT in a wrapper.
Let me also point out that LUTs or ICCs are not a valid tool for a perfect color matching on a capture device. LUT is to be used to change a look or to adjust for some known invariable (like s-curve, or log). The reason they are not a valid tool for a capture device color management is that what you capturing is moving target: light changes, subject changes, exposure changes, iso changes, the device (sensor) changes throughout a take too. The only two useful scenarios I see are
a) you have a studio setup with fixed light and neutral walls, with the same camera settings same iso, same exposure, same lens, same everything - go ahead create a profile and use it for all of the work you do with all the same settings you have created profile with (catalouge shooting?)
b) you shoot with more then one camera and you want to align them to each other in order to remove one of the variables in a grading process - shoot calibration chart with two of them in the same setup (fixed source of light (ideally close to the sweet spot of the sensor (ie some sensors are best performing at 5000k), with the same settings and the same exposure. Create your profile and then use it in a first step of color grading. Needless to say that you cannot shoot your target in a still mode and then use created profile to process video footage. You must shoot in video mode and then capture a frame
I have a strong feeling that icc profiling is not worth it for video or any other capture device. But by all means shoot a CamAlign chart with each take to assist in grading later.

Well... a pair of an original video file and a modified video from AE after applying the color profile converter effect. If you don't have, that's fine. Thanks for the tip.

Do you have any sample video?

I don't use aftereffects, are those export setting for generating lut. If so that is wonderful news. I normally work in Avid / final cut and then sent to Color for grading.
If I could import a Lut would be great for projects.
I really don't understand those attachments but i'll be opening AE and playing a little bit.
thanks, will ask questions afterwards