The question was asked. What is the best calibration equipment?
Although a bit long, the answer I gave is the base of most digital exposures, so it is supplied here for review.
My
selection for a calibration unit is the Mac Beth I-one.
that is pronounced eye one. around $200. or less.
HOWEVER!
To talk calibration, we need to understand, what it is, and what that does.
What
calibration does
is measure the output of your monitor over a range of colors including gray.
The
software measures the brightness range of the monitor so it know what is
available.
Said
another way, let's say you monitor gets a signal from Photoshop to produce pure
Red. Now the digital equivalent for
PURE RED is
Meaning
full red channel, nothing in Green and nothing in Blue.
BUT,
your monitor produces 252,3,5. That needs to be adjusted. That is
where the calibration software comes in.
The
sofware builds a profile of numbers that corrects the deficiency, so your
monitor produces 255, 0 ,0. And it does that for 35 colors, Black, White,
and Gray tones.
And
more importantly, produces neutral 18% gray as 128,128,128 on your monitor.
When that happens, your monitor is "neutralized of
stray color". And what you see
is what you will get from the lab.
Which,
the 128,128,128 is the reading you should get, when using INFO, and
the color measurement tool, when you measure a gray card image in Photoshop.
There is another step to perfect exposure.
Making
sure that your meter is measuring and has the same sensitivity as your camera's
capturing digital chip!
"Yes
Sally, there is an AP for that".
Take a known value 18% gray card.
Set it up on stand.
One light from 44 degrees. Set
ISO to be the same on camera and meter.
Measure flash exposure at the gray card.
Try for F-8, but not absolute. Set
camera for what ever hand held meter says.
Make one exposure.
Take image into Photoshop. Curser
over eye dropper and hold left mouse button to reveal other tools.
Select color measurement tool.
Put eye dropper in gray area and click.
That locks the reading. If it
says 128,128,128…turn out the light, make some popcorn and watch a movie.
But it won't…if the red channel says over 128,
you are overexposed. Adjsut the
light back 6 inches, and make another exposure.
ackMake another reading of that exposure.
When the red reads 128, or very close, NOW. take
another reading at the gray card with your hand held meter, and note the
exposure change. That change is the
difference between your meter and your camera chip.
The same applies if the first reading is below
128. Move the light forward 6
inches, and repeat until you get the proper reading.
Let's say the difference was over by .3, three
tenths. Depending on your meter
type, that .3 adjustment can be made on the meter.
If it cannot, then you adjust the ISO on the
camera to lie to the chip by 1/3 of a stop.
If
over, and camera ISO was set at 100,
raise to 120.
If low, change to ISO 80.
Leave your meter alone.
But the best way is to adjust meter if possible.
When this test is done, your exposures will improve.
Digital capture is far more exact than with film.
It captures more subtle colors, and tonal ranges
than film could ever do, but the exposure is the most critical calculation in
digital photography. If your
photographing the grand canyon, the meter in your camera works great.
If your photographing a baby on a white throw rug, it will not.
As always with me, you ask a simple
question, and you get three pages of answer, but there are no simple
answers in this profession.
Bruce