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CRT versus LCD

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September 9, 2005 8:49:08 PM

Archived from groups: rec.photo.digital (More info?)

How come my 19" CRT supports 1600x1200 while to get this with an LCD
requires at least a 21?"
-Rich

More about : crt versus lcd

Anonymous
September 9, 2005 10:50:34 PM

Archived from groups: rec.photo.digital (More info?)

Scott Schuckert <not@aol.com> wrote:
>In article <4XmUe.211$LS5.62@newsread3.news.pas.earthlink.net>, Peter
><nospamplease@rsii.net> wrote:
>
>> > How come my 19" CRT supports 1600x1200 while to get this with an LCD
>> > requires at least a 21?"
>> > -Rich
>>
>> It has to do with viewable area. CRTs have unviewable areas
>> on their edges, while all pixels on LCDs are viewable. It's the
>> same reason why most LCDs have thinner bezels than CRTs.
>
>Actually, no. That would be the other way around.

He's right... but so is what you say below.

>Your CRT can be driven to 1600X1200, but it probably doesn't look good
>that way. It's probably best at 1024X768, or a bit more. LCDs, being
>inherently digital, look great at their normal resolution, but can't be
>driven higher - and only work very poorly at lower resolutions.

The point is that with an LCD the display area itself is
/digital/ (with discrete hardware and discrete electrical
signals), being that each pixel is a specific point source of
light. There are x number of them used to build the display,
and that is how many (at most) can be lit up. So a 1024x768
resolution display has a matrix of 1024x768, and *nothing* will
cut it finer.

A CRT on the other hand has an inherently /analog/ display area.
There are several factors that determine the effective
resolution, but primarily the size of the electron beam is one,
the area that lights up when hit with the beam is another, and
bandwidth is one more. Bandwidth is very important, because
even if the size of the other two is small it won't be useful if
the bandwidth does not allow the signal to change fast enough to
make two of the smallest possible areas light up at
significantly different levels.

And note that an analog display can be /configured/ for higher
resolution than it is actually capable of effectively
displaying. Just because it appears to be "working" at
1600x1200 doesn't mean it produces any finer resolution than it
does when configured for 1024x768... and it might actually be
worse too.

Effectively, the digital display has only one restricting
specification, while the analog display has at least three. And
since the digital display deals with discrete components (both
electrically and physically), it doesn't get "out of adjustment"
as it ages, while an analog devices tends to do exactly that.

--
FloydL. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
Anonymous
September 9, 2005 11:02:55 PM

Archived from groups: rec.photo.digital (More info?)

AZ Nomad <aznomad@PmunOgeBOX.com> wrote:
>
>My last CRT is a 22" and I bought it used in '01 for $250. My next monitor sure
>as hell isn't going to be a CRT, but I'm not quite prepared to pay $700 to get
>an LCD that can do 1600x1200. Of course, a recent popular trick is to get two
>cheap 17" LCD's and put them side by side for 2560x1024 resolution.

The prices are already low enough to make two 19" LCD displays
worth doing. Last December I got over excited while on a trip,
and bought two of them on sale while Christmas shopping. They
replaced two 17" CRTs, so using two monitors was not new. (This
is on a Linux box running X.)

But the shocker for me was when I replaced the old Matrox dual
head (analog) video card with a card that had one digital and
one analog channel... which convinced me within about 20
seconds of looking at the first few images that I needed *two*
digital channels, not one digital and one analog. The
difference between the two is *very* distinct.

The only downside that I've found to using LCD monitors is that,
because of the slower response time, anything that moves gets
dimmer. Scrolling text is much harder to read, and a moving
cursor can be very difficult to spot if the contrast is low
already.

The number of advantages is just too long to list... ;-)

--
FloydL. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
Related resources
September 10, 2005 1:14:40 AM

Archived from groups: rec.photo.digital (More info?)

"Rich" <none@none.com> wrote in message news:t8t3i1h20pesqnnmm356duq9ghiabt2o4v@4ax.com...
> How come my 19" CRT supports 1600x1200 while to get this with an LCD
> requires at least a 21?"
> -Rich

It has to do with viewable area. CRTs have unviewable areas
on their edges, while all pixels on LCDs are viewable. It's the
same reason why most LCDs have thinner bezels than CRTs.
Anonymous
September 10, 2005 1:14:41 AM

Archived from groups: rec.photo.digital (More info?)

In article <4XmUe.211$LS5.62@newsread3.news.pas.earthlink.net>, Peter
<nospamplease@rsii.net> wrote:

> > How come my 19" CRT supports 1600x1200 while to get this with an LCD
> > requires at least a 21?"
> > -Rich
>
> It has to do with viewable area. CRTs have unviewable areas
> on their edges, while all pixels on LCDs are viewable. It's the
> same reason why most LCDs have thinner bezels than CRTs.

Actually, no. That would be the other way around.

Your CRT can be driven to 1600X1200, but it probably doesn't look good
that way. It's probably best at 1024X768, or a bit more. LCDs, being
inherently digital, look great at their normal resolution, but can't be
driven higher - and only work very poorly at lower resolutions.
Anonymous
September 10, 2005 1:14:41 AM

Archived from groups: rec.photo.digital (More info?)

Peter wrote:
> "Rich" <none@none.com> wrote in message news:t8t3i1h20pesqnnmm356duq9ghiabt2o4v@4ax.com...
>
>>How come my 19" CRT supports 1600x1200 while to get this with an LCD
>>requires at least a 21?"
>>-Rich
>
>
> It has to do with viewable area. CRTs have unviewable areas
> on their edges, while all pixels on LCDs are viewable. It's the
> same reason why most LCDs have thinner bezels than CRTs.

Naw... It's because LCD pixels don't have to huddle together for
protection against that nasty Cathode Ray!

:-)

Paul Allen
Anonymous
September 10, 2005 2:10:43 AM

Archived from groups: rec.photo.digital (More info?)

Rich wrote:
> How come my 19" CRT supports 1600x1200 while to get this with an LCD
> requires at least a 21?"
> -Rich

LCDs *could* be made at FAR higher resolutions.
They just aren't...

Example:
My little I-Paq Pocket PC has FAR better resolution inch-for-inch than any
LCD available.
It's 640x480, but on a mere 4" diagonal screen!
Detail is incredible.
If they'd build a 21" LCD with similarly dense pixel count...
-It would be a thing to behold.
....A 21" LCD at that density would be approximately 3100x2400 pixels...

Perhaps someday...
September 10, 2005 3:09:18 AM

Archived from groups: rec.photo.digital (More info?)

Rich wrote:

> How come my 19" CRT supports 1600x1200 while to get this with an LCD
> requires at least a 21?"

You can get laptops with 15.4" LCDs that run 1920x1200. So no technical
reason. Also external 20" LCDs with 1600x1200 aren't uncommon.

- Len
September 10, 2005 3:09:19 AM

Archived from groups: rec.photo.digital (More info?)

On Fri, 09 Sep 2005 23:09:18 GMT, Leonard <user@example.net> wrote:

>Rich wrote:
>
>> How come my 19" CRT supports 1600x1200 while to get this with an LCD
>> requires at least a 21?"
>
>You can get laptops with 15.4" LCDs that run 1920x1200. So no technical
>reason. Also external 20" LCDs with 1600x1200 aren't uncommon.
>
>- Len

I actually wanted to match a screen to my 8 meg camera, around
3500x2500. I'm wondering what happened to IBMs high resolution
CRTs?
-Rich
Anonymous
September 10, 2005 4:24:30 AM

Archived from groups: rec.photo.digital (More info?)

On Fri, 09 Sep 2005 21:14:40 GMT, Peter <nospamplease@rsii.net> wrote:


>"Rich" <none@none.com> wrote in message news:t8t3i1h20pesqnnmm356duq9ghiabt2o4v@4ax.com...
>> How come my 19" CRT supports 1600x1200 while to get this with an LCD
>> requires at least a 21?"
>> -Rich

>It has to do with viewable area. CRTs have unviewable areas
>on their edges, while all pixels on LCDs are viewable. It's the
>same reason why most LCDs have thinner bezels than CRTs.

That doesn't compute. If the 19" CRT supports 1600x1200 in a 17.5" area, it
sure has superior screen density to the LCD. To get 1600x1200 on an LCD, you
need to go to 20". A 22" (20" vueable) CRT can typically do 1800x1440.

Of course, who wants to lug a hundred pound CRT around, or lose an entire desk
to one?

My last CRT is a 22" and I bought it used in '01 for $250. My next monitor sure
as hell isn't going to be a CRT, but I'm not quite prepared to pay $700 to get
an LCD that can do 1600x1200. Of course, a recent popular trick is to get two
cheap 17" LCD's and put them side by side for 2560x1024 resolution.
September 10, 2005 4:53:01 AM

Archived from groups: rec.photo.digital (More info?)

"AZ Nomad" <aznomad@PmunOgeBOX.com> wrote in message news:slrndi49tu.cah.aznomad@ip70-176-155-130.ph.ph.cox.net...
> On Fri, 09 Sep 2005 21:14:40 GMT, Peter <nospamplease@rsii.net> wrote:
>
>
> >"Rich" <none@none.com> wrote in message news:t8t3i1h20pesqnnmm356duq9ghiabt2o4v@4ax.com...
> >> How come my 19" CRT supports 1600x1200 while to get this with an LCD
> >> requires at least a 21?"
> >> -Rich
>
> >It has to do with viewable area. CRTs have unviewable areas
> >on their edges, while all pixels on LCDs are viewable. It's the
> >same reason why most LCDs have thinner bezels than CRTs.
>
> That doesn't compute. If the 19" CRT supports 1600x1200 in a 17.5" area, it
> sure has superior screen density to the LCD. To get 1600x1200 on an LCD, you
> need to go to 20". A 22" (20" vueable) CRT can typically do 1800x1440.

You're right, I completely misread the question. A CRT does
have higher density, hence higher resolution in a given area.
Anonymous
September 10, 2005 7:48:02 AM

Archived from groups: rec.photo.digital (More info?)

On Fri, 09 Sep 2005 19:02:55 -0800, Floyd Davidson <floyd@barrow.com> wrote:
>But the shocker for me was when I replaced the old Matrox dual
>head (analog) video card with a card that had one digital and
>one analog channel... which convinced me within about 20
>seconds of looking at the first few images that I needed *two*
>digital channels, not one digital and one analog. The
>difference between the two is *very* distinct.

Absolutely; digital is a major improvement.

The next monitor I buy is going to be for my dad. He bought one of the first
LCD desktop monitors back around '96 for something like $1500 at 14" or so.
Defineately time to replace it with a modern 17" and toss in a digital video
board. He doesn't do movies, but the clarity will be a major improvement.
Anonymous
September 10, 2005 9:25:13 AM

Archived from groups: rec.photo.digital (More info?)

RadiForce R31 3MP LCD monitor comes closer to what you are looking for. It
offers 2048x1536 and comes with a contrast ratio of 400:1. It displays
10-bit colors (around 1.06 billion different colors) and costs way too much.

I use a CRT at 1600x1200 and a LCD at 1600x1200 (dual monitor setup). While
the LCD is mainly used for displaying menus, the CRT is easily calibrated
for image display. Today, you can get such a combination for less than 1K. A
good monitor with 3500x2500 would, if available, cost more than the 20D and
some really great lenses. Maybe in four years, we will get good LCDs with
that resolution. But then your "5D Mark II" will have 24 MPixels or more ;-)

Gregor


"Rich" <none@none.com> wrote in message
news:kqe4i1pv1a2gs0f0ldjakl2lgq0uin7odl@4ax.com...
> On Fri, 09 Sep 2005 23:09:18 GMT, Leonard <user@example.net> wrote:
>
>>Rich wrote:
>>
>>> How come my 19" CRT supports 1600x1200 while to get this with an LCD
>>> requires at least a 21?"
>>
>>You can get laptops with 15.4" LCDs that run 1920x1200. So no technical
>>reason. Also external 20" LCDs with 1600x1200 aren't uncommon.
>>
>>- Len
>
> I actually wanted to match a screen to my 8 meg camera, around
> 3500x2500. I'm wondering what happened to IBMs high resolution
> CRTs?
> -Rich
September 10, 2005 11:09:06 AM

Archived from groups: rec.photo.digital (More info?)

"Floyd Davidson" <floyd@barrow.com> wrote in message news:8764t962w0.fld@barrow.com...
> The only downside that I've found to using LCD monitors is that,
> because of the slower response time, anything that moves gets
> dimmer. Scrolling text is much harder to read, and a moving
> cursor can be very difficult to spot if the contrast is low
> already.

Try color correcting an image with lots of near blacks and then
get back to us. Unless one spends upwards of $2500 one will
go crazy trying to do this on an LCD. I routinely run into noise,
color casts and other image problems which are completely
invisible on my Apple Cinema Display. And that's with a new
unit (new backlight). Just a year or two from now and the
ACD will be useless even for basic color correction.
Anonymous
September 10, 2005 4:41:44 PM

Archived from groups: rec.photo.digital (More info?)

On Fri, 09 Sep 2005 18:50:34 -0800, Floyd Davidson <floyd@barrow.com> wrote:


>A CRT on the other hand has an inherently /analog/ display area.
>There are several factors that determine the effective
>resolution, but primarily the size of the electron beam is one,
>the area that lights up when hit with the beam is another, and
>bandwidth is one more.

Don't forget the mask.

-- Larry
Anonymous
September 10, 2005 5:09:57 PM

Archived from groups: rec.photo.digital (More info?)

> Effectively, the digital display has only one restricting
> specification, while the analog display has at least three. And
> since the digital display deals with discrete components (both
> electrically and physically), it doesn't get "out of adjustment" as
> it ages, while an analog devices tends to do exactly that.

Good post. One quibble, though: LCD displays do change colour over
time because the backlight ages.

> FloydL. Davidson http://www.apaflo.com/floyd_davidson
> Ukpeagvik (Barrow, Alaska) floyd@apaflo.com

Barrow, eh? I visted there a few years ago. Amazing place.

Andrew.
Anonymous
September 10, 2005 7:14:16 PM

Archived from groups: rec.photo.digital (More info?)

On Sat, 10 Sep 2005 13:09:57 +0000, Andrew Haley wrote:

>> Effectively, the digital display has only one restricting
>> specification, while the analog display has at least three. And
>> since the digital display deals with discrete components (both
>> electrically and physically), it doesn't get "out of adjustment" as
>> it ages, while an analog devices tends to do exactly that.
>
> Good post. One quibble, though: LCD displays do change colour over
> time because the backlight ages.
>
>> FloydL. Davidson http://www.apaflo.com/floyd_davidson
>> Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
>
> Barrow, eh? I visted there a few years ago. Amazing place.
>
> Andrew.
I've got one in my garden and find it useful:-)
--
Neil
Delete delete to reply by email
Anonymous
September 12, 2005 4:12:19 PM

Archived from groups: rec.photo.digital (More info?)

On Fri, 09 Sep 2005 21:48:47 -0400, Rich wrote:

> On Fri, 09 Sep 2005 23:09:18 GMT, Leonard <user@example.net> wrote:
>
>>Rich wrote:
>>
>>> How come my 19" CRT supports 1600x1200 while to get this with an LCD
>>> requires at least a 21?"
>>
>>You can get laptops with 15.4" LCDs that run 1920x1200. So no technical
>>reason. Also external 20" LCDs with 1600x1200 aren't uncommon.
>>
>>- Len
>
> I actually wanted to match a screen to my 8 meg camera, around
> 3500x2500. I'm wondering what happened to IBMs high resolution
> CRTs?
> -Rich

do a search on QUXGA (Quad Ultra XGA) and WQUXGA (Wide QUXGA) LCD
monitors. they would be 3200x2400 (UXGA=1600x1200) and 3840x2400
(WUXGA=1920x1200)

pricey, and would cost more than a 20D+ a few nice lenses (as someone else
mentioned) -- tho not quite enough to buy a 1DS MkII (maybe a D2X
body-only) IIRC, IBM had a 3840x2880 LCD a few years ago that was into
the 5-figure price range (targeted for hi-res medical imaging)

all of the above are well out of my current budget tho :( 
!