Datacolor User to User Support Group.

This is something that can be a blessing if used with a good deal of
thought given it. One benefit of camera calibration is that it will
also calibrate the meter used to determine exposure. I always use a
handheld incident meter for exposure determination and afterward use a
spot meter to see where the values in the scene fall and make needed
adjustments for the shadows. I have found the incident favors the
highlights and I don't have many blown out values there. My procedure
for calibrating my camera goes like this.

1: I place my color checker in direct sunlght evenly lit.
2: I take a meter reading and make my first exposure 2 full stops
below what the camera's ISO rating is. My Nikon D70 touts an ISO of
200, so my initial exposure is at iso 50. I then make exposures at 1/3
stop less exposure; corresponding to iso 50-64-80-100-125-160-200.
3. Opening each exposure one at a time in Camera Raw and putting all
settings on ZERO except the color temp, which I leave at the 5500
temp; I open the image in Photoshop. I use the color eyedropper and
read the values on the bottom squares to see if the fourth one from
the left is reading 127,127,127 which indicates middle gray (Zone
V-five for Zone System users). The exposure that gives me that reading
on that square is the film speed I dial into my handheld incident
meter and also my spot meter so both meters will result with identical
exposures for evaluation of the scene.
4. I follow the instructions with ACR calibrator (either the one from
Thomas Fors or Rags Gardner) and run the script on the marked section
of the color checker image to completion. The resulting numbers I copy
down on paper and on the next image I open and make them the default
RAW camera settings for all following uses.
5. I also have my monitor calibrated and use Colorvision's PrintFix
PRO for creating printer profiles for my ink/paper combinations.

For Black and white prints I feel it is absolutely necessary to have a
good color image to start with because that way the tonal ranges will
be more accurate in starting out.

This is just my personal feelings in this matter. Your reasoning and
uses will undoubtedly be different, but that is what makes photography
so personal. We are all precious and unique.

Your friend in Photography,

Johnny Eades




--- In colorvision_group@yahoogroups.com, "Tom" <ttrostel@...> wrote:
>
> So we've all calibrated our screens and our printers.  There seems to
> be plenty of software out there to calibrate our scanners too.  There
> does not however seem to be much out there for calibrating our cameras.
> 
> This is tricky though.  The image captured is somewhat subjective. 
> Normaly I shoot with a colorchecker chart just as a reference.  I did
> however run across the ACR Calibrator script which is supposed to help
> calibrate Adobe Camera Raw when importing images.  After some
> experimentation it has turned out that under controlled lighting
> conditions even the lens used has a subtle effect on the colors
> captured by my camera.  Unfortunately after measuring my chart with
> PFP I noticed that the colors published don't (cough) exactly match
> ... which isnt unusual with large batch production methods.
> 
> How careful are the rest of you with color when capturing images? 
> Would it be accurate to say that, like printing, having the colors
> captured being pleasing is not nearly as important as being deadly
> accurate?
>