programming and human factors
by Jeff Atwood
When I purchased my last set of LCD monitors, I didn't fully understand that not all LCD panels are created equal. There are three distinct families of LCD display technology, each with their own tradeoffs and peculiarities. Before you buy a new LCD display, you should take note of what kind of panel technology you're investing in.
| Color Reproduction | Viewing Angle | Response Time | Price | Quirks | |
|
*-IPS In Plane Switching |
Excellent | Excellent | Good | Expensive | Slight color tinges may be visible at an angle. |
|
*VA Vertical Alignment |
Good | Good | Average | Reasonable | Colors shift when viewed at an angle. |
|
TN Twisted Nematic |
Average | Average | Excellent | Inexpensive | Limited to 6-bit color; restricted vertical viewing angles. |
Most panels these days are TN, which isn't much of a surprise; if a consumer has the choice between a 22" or 24" display at the same price, they're naturally going to go with the larger one. Although TN displays can be quite good, they all suffer to some degree from the genetic defects of their TN family lineage.
Right now, one of my monitors is PVA, and the other two are TN. The color reproduction is slightly more pleasing on the PVA monitor, but the TN is in the ballpark. I'm only able to tell because the monitors are literally right next to each other. What I do notice in regular use on my TN displays, however, is their incredibly limited vertical view angle. I'm no graphics designer, but even I can see that colors vary quite noticeably in intensity from top-to-bottom on my TN display. You have to keep your head perfectly aligned in the tiny "sweet spot" to see consistent vertical color on these displays. Horizontally, it's fine, but vertically, it is far too sensitive.
Unfortunately, the vast majority of LCDs on the market now are TN. You can opt to pay a little bit more for one of the few models with *VA -- if there are any available in the size you want. *-IPS is widely considered the best all around LCD display technology, but it is rapidly being pushed into the vertical "pro" graphics designer market due to the big jump in price. It's usually not an option, unless you're willing to pay more than twice as much for a monitor.
But even within the TN and *VA families, there are new improvements and variants being introduced all the time. For example, LED backlighting, which is just now catching on for laptops, should eventually trickle down to the humble TN display. That one upgrade will allow it to reproduce all 100% of the NTSC color gamut for the first time. There's a more detailed chart at LCD Resource that illustrates how the various LCD display technologies have evolved over time. I've adapted it here in simple HTML:
| Bright | Black Level | Resp Time | Color Depth |
Gamma | Sat | View Angle (H) | View Angle (V) | Input Lag | Cost | |
| TN | ||||||||||
| 20/22" TN | ||||||||||
| P-MVA | ||||||||||
| 20"+ P-MVA | ||||||||||
| PVA | ||||||||||
| 20"+ PVA | ||||||||||
| S-PVA | ||||||||||
| S-IPS | ||||||||||
| 20" S-IPS | ||||||||||
| AS-IPS | ||||||||||
| A-TW-IPS |
Don't get discouraged, though. Modern, inexpensive TN based LCDs can still perform quite well, as you can see in this review of the Samsung 245BW. The main downside is-- you guessed it-- the severely limited vertical viewing angles.
The next time you set out to buy a LCD, be informed about the underlying display technology you're getting. If you're in the market, I recommend paging through the excellent LCD Monitor Buying guide at X-bit Labs, which covers that crucial aspect, and much more.
Wait, where does Average fall compared to Excellent and Good? If there is nothing below Good, does that mean that Average is between Excellent and Good? Or are there two other choices below Average that just don't exist for these three types of LCDs?
David on November 2, 2007 4:14 AMAverage -- Good -- Excellent
If you're looking for numbers, I suggest you read the X-bit Labs article and drill down into the review data for individual LCDs.
http://www.xbitlabs.com/articles/other/display/lcd-guide-f2007.html
Jeff Atwood on November 2, 2007 4:23 AMI wondered what it meant that my LCD TV said 'In Plane Switching' on it, but didn't need to know that to appreciate the amazing colors! People comment on it, especially when I turn on Discovery's Planet Earth in HD.
Now I know, though!
In case you're wondering, it's a Syntax Olevia 26" HD-ready that I bought about 10 months ago for only $450. I love it!
Tim on November 2, 2007 4:27 AMHey Now Jeff,
As always very informative, now I know all LCD monitors are not created equal. I gotta trust a triple monitor guy like you. That buying guide you linked to looks like a real good resource to have.
Coding Horror Fan,
Catto
Jeff: Thanks for another useful post and link to the LCD monitor buying guide.
Would you please change your blog behavior so that when I click on the "Read older entries " link at the bottom of the page, it takes me to the next page of entries, rather than a specific older entry?
The current configuration makes it difficult to read through your older posts, and I often find that I stop after the first page.
Looks like the aluminum 24" iMacs have an H-IPS display. That certainly makes the prices on them look more competitive.
Rafe on November 2, 2007 6:28 AMThanks for bringing this to my attention :)
I went out and read the full article, and am excited my Dell monitor (2407WFP) falls into the S-PVA class. Always been happy with it :)
David Cumps on November 2, 2007 6:37 AMJeff, I think Catto is trying to mess with your head. :)
Are you ever going to write about coding again? (And no, "I love makefiles" and "I love regexes" do not count as "coding" entries.)
Anonymous Cowherd on November 2, 2007 8:22 AMWhere does one find what technology the Apple monitors use? I have the 23" LCD and can view it at any angle (even near 180 degrees vertical or horizontal).
Dave on November 2, 2007 9:16 AMI wish I had found this earlier, although I really can't complain about my 204B Samsung. I really wanted the 24 inch version, but I went with what I could afford. And I was tired of reading about 1280x1024 when I knew I wanted 1600x1200, just like my CRT (that died a month after I got the flatscreen - at least I knew it was dying before hand! :)
But definitely something I'll keep in mind when I decide to get that second monitor. And I will be getting one before too darn long.
Bryan Price on November 2, 2007 9:32 AMI couldn't find a definitive source, but it looks like the Apple Cinema displays are mostly S-IPS panels.
Jeff Atwood on November 2, 2007 10:49 AMGlad that I decided to come take a look at your bog today. I just sat down this afternoon and started looking around for the LCD screens which I'll be using on the new system that I'm building. Now it looks like I have a whole new set of criteria to think about before making my choice. Excelent read as allways, and very informative.
FireCracker37 on November 2, 2007 12:49 PMPart 2: What's a Panel Lottery, and Why You Might Want to Play
Because S-IPS panels tend to be adopted by more high-end manufacters (like Apple and NEC) most end up being quite expensive. The good news is that some S-IPS panels make it into mid-priced monitors too. The bad news is that many of those suffer from the "panel lottery" problem. A panel lotery is when a manufacturer decides to ship different panel types under the same model designation, forcing people to either "buy blind" or figure out some way to tease the panel type information from the manufacturer's cryptic serial numbers ans revision codes.
Of course you can always count on someone somewhere doing the latter: here are the HardOCP forum threads for the HP LP2065 (20" 4:3) and the Dell 2007FP and 2007WFP (20" 4:3 and 16:10 respectively):
http://www.hardforum.com/showthread.php?s=6bdeb2bb45aae94ea0519cfbc34af949t=1162417
http://www.hardforum.com/showthread.php?t=1111100 (all the info you need is in the first post)
Armed with this information there are 3 possible strategies:
- If you can get it from an online store with a good returns policy, order one and hope for the best (this is the lottery part :). If you get the non S-IPS version just send it back. This appears to work well when ordering direct from Dell, for example.
- Find the monitor you want at a retail store and check for the panel type (no lottery)
- Get it from ebay. This has the advantage that you can ask the seller for the panel identifying information (again, no lottery)
(BTW, I list 20" models because that's what I was looking for, there are probably other choices for other sizes. The exception is 24", there are no 24" IPS panels currently in the market at all, the closest you can get is the 23" Apple Cinema Display.)
Me, I got a Dell 2007FP from ebay for 215 incl. shipping. Not much more expensive than a cheapo TN panel after all!
Cheers
paol, thanks for sharing your expertise on this topic! Great stuff!
Jeff Atwood on November 3, 2007 7:27 AMYou people are clearly in need of some links :)
First, the panel database at tftcentral, where you can check the exact panel used in any monitor (may not have the very newest models):
http://www.tftcentral.co.uk/articles/panel_parts.htm
And a searchable version here:
http://www.tftcentral.co.uk/panelsearch.htm
Another similar site, but I haven't used it as much:
http://axofiber.no-ip.org/inside/monitor.lcd.panels.en.htm
(to Dave: all Apple Cinema Displays are S-IPS, as you can see from the above)
I have no idea what panel type they are, but I have a 24in Dell purchased in August 2005, and a 30in Dell purchased in July, and they both rock. The 30 cost 1200 USD, not a trivial amount but certainly less than Apple or others. I can view from any angle, practically "pencil vision" as I am looking at the side of the monitor itself almost, and they look great. Color is great( although I am not doing work for print and can't speak much for ICC perfect color ), brightness, etc. Hell, even games and movies with fast motion have no refresh issues.
I am one happy coder.
The Foo on November 3, 2007 11:56 AMI thought I would post some more info, as I've recently gone throught the same discovery proccess as Jeff. I was hanging on to my aging Sony 19" CRT but it started dying on me and, according to Sony, could not be fixed, so I set out to find an LCD that didn't suck.
I would recommend anyone serious about display quality to read up on it a lot before buying, as there a lot more to it than I could cover in this comment. Don't even bother with panel "reviews" in sites like cnet and such, those people couln't tell an LCD from a CRT if it dropped on their foot. Specialist sites like tftcentral.co.uk are a better place to start.
Also, be aware that different uses and different individual sensibilities means that not everyone will benefit from the "better" panel types. If you're happy with one of the supposedly inferior panels, by all means get it and spend the leftover money on something else.
That said, for me it was S-IPS or bust. Here's why:
- TN vertical viewing angles are just hideous. This isn't just theoretical either, my work assigned portable has a TN panel. Even though it's only a 14" I can stand still and see a strong color/brightness/contrast gradient from top to bottom. In eclipse which uses tiny colored markers along the right edge of the editor to signal errors, search matches, etc, I find myself cranning my neck up and down just to seem them at all. Light colors on light backgrounds often become completely invisible below the middle of the screen, and the same for dark colors above.
- PVA and MVA are better but suffer from their own angle problems, this time in the horizontal. A single solid color across the monitorwill appear darker directly in front of your eyes and lighter toward the left and right. Some people seem ok with this, others swear it drives them crazy due to the "sheen" efect caused by each eye not seeing the same color (slightly different viewing angles you see...) I checked out PVA panels in stores and the sheen effect was clearly visible, so I decided to steer clear of these.
- The response time argument in modern panels is a red herring IMHO. TN film panels have the lowest figures, but any decent IPS or *VA panel today will have 8ms grey-to-grey, which at least to my eyes is more than good enough for gaming.
After the break: how to win a S-IPS panel in the lottery, without breaking the bank :)
Good article Jeff.
Your HTML chart has two problems though:
1) There is no key/legend.
2) I am slightly color blind so I am unable to easily match the colors on say the TN row with the A-TW-IPS row. For example TN View Angle(V) looks the same as A-TW-IPS Cost to my eye. (I use utils called Zoomplus and WhatColor to help me out here).
Interestingly I'm using a TN LCD panel so the vertical color variance probably makes things even harder for me.
Ash on November 3, 2007 1:31 PMHardForum should be everyone's first stop when searching for an LCD. They have massive threads discussing everything - from backlight bleeding, to colour shifts and weird firmware quirks.
That said, after going through their Displays subforum, I decided to stick to my old CRT for a while. LCD just doesn't seem there yet, everything has its quirks. TN isn't an option, *VA annoys the hell out of me, and *IPS monitors are either too expensive, unobtainable, too small, too big, or have problems with backlight bleeding.
I'm waiting for OLED and SED. Should my CRT die in the meantime, I'll buy a cheap, used one.
Johnny Guitar on November 4, 2007 5:12 AMVery informative, as always. People just don't realize how bad some typical monitors are. The cheap Dells being supplied to big government departments in Canberra are so poor it is hard to read text and see all the parts of an start menu icon, let alone view photographs.
Some LCD monitors which claim to have good color do not: they dither very few colors to achieve an illusion of more (and therefore flicker and ripple). Many have woefully inaccurate palettes and greyscale (my 2nd monitor even displays some oranges as yellow and it's gamma varies at different angles of view).
For those with a good monitor budget, I heartily recommend Eizo: first monitor I have had which was correctly calibrated out of the box (and most that I have had which were not could not be completely calibrated anywhere near as accurate as the Eizo accomplishes effortlessly). Rock solid off-axis as well (unless you are almost side-on).
Visitors are still stunned by the vividness of photographs (and how poor my second monitor, an average Mitsubishi, looks in comparison).
Sadly, they are not cheap, but if you stare at one all day, worth every cent. Of course, an accurate greyscale and color palette can only make text easier on the eyes as well. And a good monitor can last several computer upgrades without needing to replace it.
Paul Coddington on November 4, 2007 7:33 AMWhat the heck happened to your feed count?
Jason on November 4, 2007 10:33 AMNow if only there was a good LCD HDTV buying guide. I am so confused on which TV to buy. I guess one of the main confusions is whether Samsung is better than Philips in this area?
Vaibhav Gadodia on November 4, 2007 10:52 AM@paol: there are no 24" IPS panels currently in the market at all
FYI, NEC MultiSync LCD2490WUXi has S-IPS panel (A-TW-IPS LM240WU1 by LG.Philips).
CW on November 4, 2007 11:51 AMHow are those Samsung 245BW screens working out in daily use? Are the limited viewing angles a noticeable distraction when coding? What about the glossy frame?
I have been trying to decide between the Samsung 245BW, a Dell 2407WFP-HC, and a BenQ FP241W for similar use to yours.
CW: Missed that one. It does appear to be the only choice though... and being a NEC WUXi it's probably
- glossy
- way over my budget
So I guess I didn't miss much :)
PS Nice site! Why does it only cover 24" displays?
@paol: The NEC WUXi displays are not glossy. It is a bit pricey however.
John on November 5, 2007 9:36 AMI recently learned about the vertical quality the hard way and it hurt big time. Next time I buy a new screen I will be very careful.
This is the good screen: Samsung 226BW
And this screen sucks when compared to the above screen: ViewSonic VA1912WB
To make a long story short (the long version is on my blog), the ViewSonic can't be used in a vertical position.
henrik sarvell on November 5, 2007 12:08 PMHow about power usage?
Sunnan on November 5, 2007 12:25 PMI use a CRT (Trinitron Multiscan G500) as my primary and a sketchy LCD (Viewsonic VG910s) as my secondary display. I paid $50 plus lunch for my boss who kindly picked up the CRT off of craigslist. It replaced an aging Trinitron of an older model (G410, notorious for contrast gradually increasing over time). Before I got the G500, I was using the LCD as my only display.
One of the other commenters claimed the response time on LCDs is fine for gaming. When I started using the LCD as my primary, I couldn't quite put my finger on what was wrong, but it was disorienting. You can definitely get used to it eventually, but it is something that's going to cause eye fatigue. Maybe my LCD is a little on the craptacular side and there are better performing LCDs, but I'd still rather have a CRT for a primary. Comparing equally priced CRTs to LCDs, the CRT is going to out perform the LCD.
chris on November 6, 2007 4:08 AMI have always wandered: The current LCD's cover the sRGB color space as they should. If they were to cover NTSC color space, they WOULD be able to display more colors, but in normal use all colors would be WRONG because of the color mapping.
So covering NTSC colors would only be usable to graphic designers, because they use software, like Photoshop, which can understand color profiles.
So my advide to developers would be: don't get LCD's with LEDs because you will get all colors wrong any you will pay additionally for that 'feature'.
Or am I wrong?
I have always wandered: The current LCD's cover the sRGB color space as they should. If they were to cover NTSC color space, they WOULD be able to display more colors, but in normal use all colors would be WRONG because of the color mapping.
So covering NTSC colors would only be usable to graphic designers, because they use software, like Photoshop, which can understand color profiles.
So my advice to developers would be: don't get LCD's with LEDs because you will get all colors wrong any you will pay additionally for that 'feature'.
Or am I wrong?
Informative post. At work I'm running two 19" Dell LCDs, both rotated 90 degrees. One is a 1905FP and the other a 1907FP. ONE of them has a terribly limited vertical viewing angle. And since I have them rotated to portrait orientation, if I shift my head slightly left or right, the "bad" one gets either dark or washed out. (It sucks to be me). I'm guessing it has something to do with this "TN" or "*VA" technology.
I can't recommend the Samsung 226BW to anyone except for light general duty and perhaps gaming. The response time is very good but the color is so inconsistent its infuriating. Even slight changes in the viewing angle can dramatically change the color, making Photoshop work difficult at best.
Scott on November 7, 2007 9:01 AMbest LCD buying guide around:
http://forums.anandtech.com/messageview.aspx?catid=31threadid=2049206enterthread=y
Matt on November 7, 2007 12:47 PMCan anyone recommend a 22" widescreen that can be rotated in portrait orientation? Or is that something that the bigger screens just don't do? I'm using a 20" widescreen in portrait mode at the moment, and it's great.
Matt on November 11, 2007 9:56 AMTo find out what type of LCD is used on a Mac, use the utility "SwitchResX" (don't know what to use under Windows). As "Looby" says at http://discussions.apple.com/thread.jspa?messageID=6009076:
"Click on "Export DDC" to dump the panel's DDC info block to a text file. The last few lines of that file show the manufacturer's part number -- as reported by the panel itself. Once you have the part number, you can find the panel's specs (and a list of other products that use the same panel) in http://tftcentral.co.uk 's panel database."
John Sawyer on December 2, 2007 12:46 PMSpeaking of Eizo, it seems that they use TN panels, too. While the TN monitors are quite good compared with other TN monitors and have excellent adjustability and mechanical quality, the picture quality just is not there yet. I fell into this trap myself. Now the Eizo is going back and the old CRT is back on my desk. I really miss the screen area.
OJ on February 6, 2008 4:03 AMim actually looking for non-tn panels.
hi which monitors are you using currently? which ones would you recommend?
enk on March 21, 2008 12:51 PMApparently the NEC 2490 WUXI is the best 24" around (IPS). That one is not available in NZ, so I think the next one down is either the Dell 2408 or Samsung 245T (both use the same/equivalent panel, S-PVA). Unfortunately both suffer from input lag, but the Dell is about 1/3 cheaper than the Samsung and a new revision is due out in a couple of weeks which seeks to address its myriad or problems.
Such problems include uneven backlighting, red hue on the left side of the screen and halos around text due to the sharpness setting.
For LCDs which have pixel perfect accuracy, I dont know why there is even an option for sharpness.
Andrew on June 8, 2008 4:04 AM@enk If you absolutely, positively want to avoid TN, then buy an Apple monitor. It's the only brand I know of that never uses TN -- to Apple's credit.
All other brands, you have to research the panel type!
Some relevant links:
AnandTech LCD Thread
http://forums.anandtech.com/messageview.aspx?catid=31threadid=2049206enterthread=y
PRAD buyer's guide
http://www.prad.de/en/monitore/buyers-guide/graphic24.html
Display section of the [H]ard|Forum
http://www.hardforum.com/forumdisplay.php?f=78
FlatPanels Panel Search
http://www.flatpanels.dk/panels.php
TFT Central
http://www.tftcentral.co.uk/search.php?query=select=model
Hey Jeff, you got quite a good thing put up here....
I struck up something relevant but more on the niche of displays in today's world and the progress in this side.
Here's a a href=http://s-tech-inc.blogspot.com/2008/10/future-of-displays.htmldisplay review/a that concerns with the inside working on lcd's and why they cant be viewed at an angle.
Hey Jeff, you got quite a good thing put up here....
I struck up something relevant but more on the niche of displays in today's world and the progress in this side.
Here's a display review
http://s-tech-inc.blogspot.com/2008/10/future-of-displays.html
that concerns with the inside working on lcd's and why they cant be viewed at an angle.
Hi Guys
Any idea which is the better of the TV panels made and who are the main manufactures of TV panels 40 42inch. I am cosidering buying a new LCD TV. I was told that Samsung and Philips are both good.
GKAP on January 4, 2009 11:49 AMThank you very much for the great information.
Thanks
a href=http://www.flipmusiccharts.info/flip music charts/a
I think that most people won't even bother about underlying display technology they are getting when they are buying TVs. Just take a look at the marketing gimmicks they are pushing now with LED TVs. Most aren't really LED TVs. They are only LED backlit, LCD panels essentially.
James
Technology Enthusiast
Cellular Deals
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