This is all very nice for watching movies or gaming on the monitor but it's pretty worthless information to photographers who mostly need an accurate impression of how an image will appear on paper which is not very contrasty at all.
What on Earth would you do with the data obtained from reading the screen with a lightmeter?
The trivia that ends up lying around clogging the space between the idea and the image is unbelievable
herschel
karl shah-jenner <shahjen@xxxxxxxxxxxx> wrote:
karl shah-jenner <shahjen@xxxxxxxxxxxx> wrote:
From: "David Dyer-Bennet"
: Hang on; people have been telling me that the fatal flaw in the LCD
: screen is *lower* contrast than on CRTs. No?
http://en.wikipedia.org/wiki/Contrast_ratio
it seems as usual, there are differing ways of measuring and expressing the
idea of contrast ratio, one considers the available room light, another
method does not. ANother method highlights dynamic contrast advantages
over static
"Emissive display technologies - where all pixels emit light individually,
such as OLED, plasma, FED and SED - are capable of achieving a very good
contrast ratio. This is also true with the case of CRT[1] which have a
theoretically infinite contrast ratio and practically achieve such a high
contrast ratio that this terminology usually does not refer to them."
this is largely because the light is emitted when the gun in the CRT causes
light to be emitted when it fires at the phosphor screen at a given part of
the screen, the comparison being against the bit where NO emission occurs,
thus no light. LCD' have a light that's always on and black is produced by
blocking this light. There's a limit to how much can be blocked, and a
limit to how bright the LCD backlight can go (obviously) and the difference
between the two limits LCS's more than CRT's, OLED's or any of the others
mentioned above
Personally I have great hopes for OLED's and hope we see them on the market
soon. Prices should be VERY cheap and sizes are not limited by existing
problems in technology as the screen can be created by virtually 'printing'
it on a substrate :) :)
"A notable recent development in the LCD technology is the so called
"dynamic contrast". When there is a need to display a dark image, the
display would underpower the backlight lamp ..but will proportionately
amplify the transmission through the LCD panel. This gives the benefit of
realizing the potential static contrast ratio of the LCD panel in dark
scenes... The drawback is that if a dark scene does contain small areas of
superbright light, they may be sacrificed and blown out."
"Some manufacturers have gone as far as using different device parameters
for the two tests, even further inflating the calculated contrast ratio. ..
one method to do this is to enable the white sector for the "on" part and
disable it for the "off" part[4] This practice is rather dubious, as it
will be impossible to reproduce such contrast ratios with any useful image
content."
There is of course a way to work it out, after all we're photographers and
thus probably likely to have access to a light meter ;)
it would be a simple matter of setting a desktop background to black,
bringing up a white page and in a darkened room measuring the light values
of each !
k
Herschel Mair
Head of the Department of Photography,
Head of the Department of Photography,
Higher College of Technology
Muscat
Sultanate of Oman
Muscat
Sultanate of Oman
Adobe Certified instructor
+ (986) 99899 673
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