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What The ED Can Do For Digital Photos What The ED Can Do For Digital Photos
ExpoDiscs are multi-element filters that friction-fit into the front of your camera
lens to provide you with the ideal tool to achieve White Balance on the First
Proof, without the problems caused by gray or white cards. They are faster,
easier and more consistent than all other options. Simplicity of use allows the
photographer to concentrate on the subject with fewer distractions for all
involved. The ExpoDisc is lightweight, maintenance-free, battery-free, and
virtually indestructible, and is also a handy weatherproof lens cap.
With so much going for them, you may be wondering why the ExpoDisc isnt
automatically provided with new camera lenses, and has not been available in
camera retail stores. When George Wallace came up with this near-perfect,
inexpensive, maintenance-free, and virtually indestructible key to almost-instant
versatile metering options, he anticipated a tremendous response from the
camera industry-but it didnt happen. A representative of one of the major
manufacturers told him:
George, my company spends millions of dollars every year telling the
world it needs our sophisticated exposures systems. Theres no way were
going to tell them that a cheap add-on does it better ExpoDisc methods give you perfect white balance on the first proof,
with rich saturated colors, luminous whites, and velvety blacks,
allowing in-camera processing (jpeg, tiff) that doesnt require later
color correction. Many photographers who formerly used only RAW have
switched to HQ JPEG using ExpoDisc methods - see our
EXPOPHOTOS
GALLERY
to view the results they are getting (all images have been
downloaded without any color correction). ExpoDiscs work in conjunction with built-in sensors and software to
instantly create an accurate white balance reference regardless of
the light source (incident or reflective light, including all mixed light
and flash) or the color of the subject (including close-ups, and subjects
lacking very light objects or having one dominant color). The multiple
facets of the prismatic lens (more efficient than a dome) collect multiple
samples of light from 180 degrees, scrambling it to create an accurate
average (in the correct proportion) of all light that contributes to subject illumination. A white diffusion disc provides even illumination across the
full frame, and the appropriate color-correcting filters are sandwiched in-
between during assembly to create units which are individually color-
corrected to within 3% of being perfectly neutral. Each unit is provided with
a card noting its precise color rating and density. No other commercially
available product can provide this level of accuracy. ExpoDiscs can be used to meter incident light and set exposure in
one step, thus eliminating common exposure errors caused by reading
intricate dials and meters on external equipment and translating the
information to separate camera controls. Use this exposure to record a
gray frame that can be used to set white balance for all images shot
in the same light, and with the same lens - you will download perfect
exposure levels with neutrals that are automatically color-balanced at
acquisition, and all colors in general will be more pleasing. Use the ExpoDisc to check or calibrate your camera meter for
accuracy. There is no constant universal standard for meter calibration -
each manufacturer can set their own standard, and meters from the same
manufacturer when independently tested have varied by as much as two
stops (see
article by Joe Englander
on our website, under
ARTICLES &
REVIEWS
). In addition meters can be jarred out of calibration,
accumulated dirt can cause fluctuation, and battery defects can cause
meter readings to drift. Does your meter give a reliable reading and does it
do it at all levels of illumination? All meters should be calibrated at least
once a year, but it's prudent to do it often since it takes only minutes on a
clear sunny day. Inaccurate meters are responsible for many exposure
errors that are frequently attributed to other causes. Also check your meter's spectral sensitivity, because you'll probably
be surprised! Joe Englander also describes how to use the ExpoDisc to
see if your meter has the ability to read through filters or if it is lacking in
spectral sensitivity (see our website for his
article from Camera &
Darkroom, Oct 94, page 63
). This procedure is more involved but if you
are not getting the results you want, it is critical, considering how much
you depend on your meter. With this procedure you can use the ExpoDisc
to calibrate your meter to the same critical tolerance you require from your
other photographic equipment. If you want to use a spotmeter with a
polarizer, meter through an ExpoDisc for perfect results. ExpoDiscs give the most accurate exposures possible, free of
surface glare or reflected light or color and without chance of lens
flare. Subject brightness levels do not mislead them, even with very
light or very dark subjects (built-in meters are programmed to provide
constant middle-value image tones). The ExpoDisc meters the actual
amount of light entering the lens, and with it the camera meter automatically compensates for all changes which aperture errors, filters,
tele-extenders, etc., may have on exposures. Hand-held meters cant
possibly allow for the effects of filters, extended image distances, or
varying transmission characteristics in different optical systems. Used for research and medical applications, ExpoDiscs enable
digital documentation accurate at point of capture - providing
irrefutable data for legal evidence and for early diagnosis. Digital
photos used to study tissue samples will replicate accurate colors at
acquisition, eliminating all post-processing procedures that would
compromise the value of the images for legal evidence. ExpoDisc
methods enable progressive documentation so consistent that a
computer-generated comparison would detect a shift in tissue color long
before it could be noted by the human eye - thus providing a valuable
diagnostic tool for early diagnosis of tissue-related diseases, and also for
forensic applications. ExpoDiscs are 100% guaranteed. They should last a lifetime, and
serve equally well on any film or digital camera, digicam or video
camera/ camcorder that you own. Detailed instructions are included for
film and digital applications, and more extended applications are available
on our website under
TIPS FROM THE PROS
and
INSTRUCTIONS
(read
tips for all camera models - there are many generic tips that apply to
everyone). If your camera model requires a different sequence of steps
than those posted, follow the manufacturers instructions for shooting a
gray card, making an exposure through an ExpoDisc instead of aiming at
a gray card. You can even use this last method to create a custom white
balance when the camera itself does not provide that option - read how
under
TIPS FROM THE PROS
. We invite you to submit suitable
instructions for your model, which we will gladly post here.
ED vs. The Gray Card
THE EXPODISC MAKES GRAY/WHITE CARDS & STYROFOAM CUPS
OBSOLETE When mounted on the camera lens (instantly available when used like
a lens cap) it always provides a convenient and fast full frame image
of a perfect neutral gray frame. The ExpoDisc procedure for setting
WB takes only 60 seconds per batch, about as long as it used to take to
change a roll of film - and you get perfect WB on the first proof! Each ExpoDisc is individually analyzed and corrected to be accurate
to within 1/12 f/stop for exposures, and within 3% of absolute perfect color
balance . It comes with a card recording its exact density and color
balance as noted on the color analyzer. There is no other product
available which can even approach this level of accuracy. Different brands of gray cards are different colors of gray, there is no consistency. The
ExpoDisc is far more neutral and accurate than commercial gray
cards that have poor quality control and can be well off the beam. The ExpoDisc will never be plagued by the many variables that
diminish the accuracy of gray/white cards: glare and lens flare,
reflections, angles and shadows. The performance of the ExpoDisc will never be affected by getting dirty or
wet. It is weatherproof, and it will never fade. There are also huge advantages gained by being able to set WB from
the shooting position . No more trying to fill the frame with a shot of a
card which is too small to fit the frame from a reasonable distance, and is
too large to comfortably haul around (the ExpoDisc can fit easily in your
pocket). It is also the easiest way to set WB when the subject matter lacks
white, or is too light or too dark, or when there is a single dominant
color in the image. The ExpoDisc provides the only way to set white balance in mixed
light. It averages total available light (including flash when used) collected
from 180¤. When you use the ExpoDisc to meter incident light you can select the
fastest exposure possible. First determine the largest aperture you can
use for the depth-of-field (20 seconds using the Wallace Aperture Guide),
and then use the built-in meter to set the shutter speed. Shoot a gray
frame to set WB while metering through the ExpoDisc (add 60
seconds). Or you can use the ExpoDisc with reflective light to set WB only. Create your own Custom WB in camera, at point