For true colours CRTs are still top. My number one choice for a 17inch.
Written: Feb 11 '02
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Pros: 100% flat, minimal reflections. High resolution, fast refresh, sharp everywhere, good geometry, great colorimitry.
Cons: Fingerprints show badly. Not as thin as a L.C.D. display.
The Bottom Line: For true image colours CRT displays are still top. If you want a 17inch CRT display get a 795FT. Choose a good CRT display rather than limited resolution flat panel.
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| petertr's Full Review: LG Flatron 795FT Plus CRT Monitor |
LG Flatron was overall winner of the BT Global Challenge 2000/01 yacht race, taking 10 months to circle the globe going “the wrong way round”. The LG795FT monitor is a winner as well.
IN SHORT
Good contrast, minimal reflections and flare, very sharp and perfect convergence to all parts of screen, true image colours - excellent colorimitry, monitor ICM profile supplied, no noticeable colour impurities, easy menu system for adjustments with separate adjustments memory for each screen mode, useful powered USB hub.
Only downside is that fingerprints show badly. Moiré patterning can be seen, on certain dithered colours, but this is really an indication of the monitor sharpness.
I work for a major UK TV station in the technical area responsible for transmission quality, we use ‘Grade One’ (extremely expensive) TV monitors for critical work. I’m in a good position to recognise picture impairments - but not so good, in that I’m very fussy, when it comes to choosing a TV or monitor for home use.
A good monitor will probably outlast your system by an upgrade or two, reduced eye strain is worth the money.
THE SPEC
LG Flatron 795FT and 795FT Plus
17inch (16.1 viewable) colour monitor using the LG 100% flat CRT (Cathode Ray Tube).
0.24mm stripe pitch slot mask.
W-ARAS(Wide Anti-Reflective Anti-Static) anti-glare coating.
The Plus model is plus USB - a 4 port powered USB hub located on the rear of the monitor case, the hub still functions with monitor in standby mode.
The USB connectors are a bit hard to get at but at least this keeps the wires hidden.
Display modes up to 1600x1200 @ 75Hz or 1280x1024 @ 85Hz
CONTROLS
Adjustments using OSD (On Screen Display) menu using six small touch buttons on the case front, their beep may be turned off. There are controls for brightness, contrast, colour, position, size, geometry and other functions. Independent control settings are stored for each standard display mode (and up to 37 modes in total); settings are recalled on re-entering that mode.
The monitor is perfectly useable straight out of the box with no adjustment. It’s well worth setting the scan size and positioning to completely fill the screen - do this the first time each new graphics mode is used. Other than this I’ve adjusted the geometry, to get the sides top and bottom dead straight, but most people wouldn’t be aware of the difference.
When first switched on, and the monitor warms, up some things drift slightly, usually only for a few minutes, but before doing any adjustments give it an hour to ensure everything has stabilized.
Anyone with keen young button pushers about, will probably wish the buttons were hidden behind a flap.
FEWER REFLECTIONS
All CRT tube faces used to be curved in both the horizontal and vertical plane, they are like looking at a convex mirror and show reflections from above, below and either side.
Then came FST CRTs (Flatter Squarer Tubes) with faces flat in the vertical plane but still curved across, now reflections were limited mainly to just the horizontal plane – this makes a great difference.
Finally there’s really flat CRTs, face flat in both planes, now only lights in one direction can cause nuisance reflections - provided the glass is also be flat on the inside of the face, as this surface can also reflect.
LG 100% flat tubes are flat both on the outside and inside, other makes still all have a curved inner face with various shortcomings due to having thicker glass around the edges.
With perfectly flat glass, refraction can cause an optical illusion making some people think the image looking concave. I’m not quite sure what you’re meant to see as in use it always looks flat to me, though I’m very aware, when switching from the 797FT, how convex older monitors appear.
The combination of flat technology and anti-glare coating improves contrast and should help reduce eye fatigue.
PITCH
The LG 100% flat tube with 0.24mm stripe pitch slot mask gives the same horizontal resolution as an aperture-grille masks of the same pitch or a standard dot mask CRT with 0.28mm dot pitch.
Over its 323mm screen width there are 323 / 0.24 = 1346 points.
Screen modes at 1280x1024 or below: everything very clear.
Screen mode 1600x1200: text viewed at180 columns across screen is still reasonably readable though some single pixel verticals appear faint; in Word at 100% zoom Arial font size 12 is comfortable to read but below 11 is a struggle (as a test I wrote this on the 795FT at 1600x1200 100% zoom with Arial size 11).
A standard dot mask CRT contains a shadow mask, a very thin metal plate perforated all over like a sieve, located just behind the glass screen. The evenly spaced holes must exactly align with the red, green, and blue phosphor dots on the inside of the screen. Adjacent red, green, and blue dots are equally spaced (so forming an equilateral triangle shape) it is this spacing which is quoted as the dot pitch. No side of the triangle is horizontally or vertically aligned, to find the pitch at which the phosphor pattern repeats horizontally multiply the dot pitch by 0.866 { = COS(30º) }.
Modified or ‘Enhanced’ dot mask CRTs (Hitachi) uses an asymmetrical dot pattern, for this type of CRT you should find the horizontal dot pitch quoted.
Slot mask CRTs have a shadow mask but the holes are short vertical stripes instead of dots. This allows greater light output, due to the smaller overall area of metal in the mask, compared to a dot mask CRT. You will find the slot (horizontal) pitch quoted.
Aperture grille CRTs that are made by Sony (Trinitron) and Mitsubishi (Diamondtron) use wires as a mask. The wires are stretched vertically in a frame between the top and bottom of the screen, with one, two, or three horizontal damper wires, regularly spaced down the screen, to hold the vertical wires in place. The gaps between the vertical wires line up with full height stripes of phosphor alternating red, green, and blue. These CRTs could give the greatest light output but suffer from dark lines, where the horizontal wires cross, that many people find objectionable. These shadow lines are most visible when viewing areas of light colour. Another potential problem is that as the monitor ages, the wires loosen slightly causing increased sensitivity to image shimmer if vibrated.
In all CRTs, because of the beam angle, the dots or slots in the mask are very slightly closer together than phosphor dots or stripes typically by 0.01mm. Sometimes the reduced figure is quoted for pitch. For standard CRTs you could see the mask pitch instead of the phosphor dot pitch, for aperture grille CRTs the grille pitch may be quoted instead of the phosphor stripe pitch.
MOIRÉ
Some slight moiré may be seen on certain dithered colours. Dithered colours are formed by making every other pixel a different colour, the eye can’t distinguish the individual pixels so sees an average colour. If dithering uses black and white pixels the result would be a grey. The moiré that is seen is a result of interference between the horizontal and vertical pixel size (display mode dependant) and the monitor dot, slot or aperture pitch. As the two get closer the patterning gets worse. With a low resolution CRT the pitch is large enough for pixel averaging within each CRT dot so preventing much moiré.
The action of the 795FT’s horizontal and vertical moiré reduction adjustments is to introduce rapid scan modulation, so dot averaging reduces steady moiré. The reduction achieved is quite limited but this scan shaking also blurs the display, some straight edges become jagged, so it’s best to keep these adjustments set to zero.
FLAT PANEL COMPARISON
CRTs will display any graphics mode that the scanning circuit will accept, scanning scales the pixels to fill the screen area.
Flat panel displays have a fixed number of cells and can display only one graphics mode at full-screen size using one cell per pixel. Other resolution graphics modes can only be displayed full-size by re-scaling. Re-scaling can result in jagged artefacts on fine text and image detail, on areas of dithered colour moiré can appear.
If using 1280x1024 screen modes then the 795FT with 1364 horizontal points will clearly give better results than a 1024x768 flat panel.
For true image colours (accurate colorimitry) CRT displays are still top for the time being. This is largely down to the control of device gamma which is very well understood for CRTs, but is some time off for domestic flat panel displays.
REFRESH & FLICKER
The sensitivity of the eye to monitor flicker varies slightly from person to person but greatly depends on the viewing method. Peripheral vision is much more sensitive to flicker, so if you sit close by a bright monitor but look to the side, flicker will be apparent if the refresh is not fast enough. Try it on your CRT monitor and your old TV.
This peripheral sensitivity is believed to have evolved for the detection of rapid peripheral movements such as predators. A result of this peripheral effect is that when you upgrade to a larger monitor, which covers a wider field of view, a refresh rate that was fine before may now cause flicker.
A refresh rate, or vertical scan rate, of 50Hz (Hertz i.e. 50 times per second) will always cause flicker that is apparent to peripheral vision. This 50Hz rate is used for UK TV. At 60Hz some people won’t detect any flicker, this rate is used for US TV. At 75Hz few will detect flicker and at 85Hz detection is unlikely. Much lower refresh rates can be used without flicker where the CRT uses long persistence phosphors, VDUs using these were often used for text displays.
The Flatron795FT can show most display modes at 85Hz refresh, though 1600x1200 modes are limited to 75Hz. You can only display at refresh rates and modes that your graphics card also supports.
CLEANING
Fingerprint marks etc. show up badly on this screen, possibly because there is so little reflection that the screen is much blacker to start with. It’s either that or the anti-static coating which makes it hard to remove fingerprints completely.
My set-up is probably a worst-case scenario for showing marks, the monitor is at right angles to a window and gets sun directly across the screen for part of the day. Luckily the kids are great at remembering to keep there paws off, the reminder stick on note probably helps!
The instructions for cleaning say “use a slightly damp (not wet) cloth”. All the sprays I’ve tried cause bad smears, so I now start with the very slightly damp end of a cloth and polish off with the dry end.
UK price £170)
Recommended:
Yes
Amount Paid (US$): 241
Operating System: Windows
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Epinions.com ID:
petertr
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Location: Knaresborough, N.Yorks, England
Reviews written: 3
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