Any non-shimmering LCDs?

They make noise, too.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
doveman
Posts: 866
Joined: Mon Jan 29, 2007 10:30 am
Location: London

Any non-shimmering LCDs?

Post by doveman » Tue Aug 10, 2010 8:57 am

I recently had a Benq G2420HDBL 24" LCD 5ms and found it unusable as the text shimmered too much when scrolling, so I returned it.

I've been advised that this is common with LCDs (I don't know how people put up with it) and indeed when checking my Dad's 22" LCD I noticed the same thing.

Apparently it might be less of a problem with 120hz monitors such as this http://www.aria.co.uk/Products/Monitors ... ctId=40350 or perhaps with 2ms ones, so I was wondering if anyone has any experience of these compared to a 60hz 5ms LCD and whether this problem is still noticeable with them.

Cerb
Posts: 391
Joined: Tue Apr 13, 2004 6:36 pm
Location: GA (US)

Post by Cerb » Tue Aug 10, 2010 9:26 am

The monitor refresh rate has nothing to do with it. I've got to go now, but that's not it. However, it would help if you were to describe what exactly you mean by shimmer. I can think if a few different things that could be that.

doveman
Posts: 866
Joined: Mon Jan 29, 2007 10:30 am
Location: London

Post by doveman » Tue Aug 10, 2010 10:04 am

Sorry, it's hard to find the right word to describe the effect but I suppose I would say that the text wasn't steady when scrolling, in that it would lose it's definition, perhaps becoming a bit fainter momentarily, which made me lose focus a bit. Maybe pulsing is the right word.

Obviously when scrolling the text is being moved anyway, so there's an element of having to refocus, but with my CRT the text always maintains it's colour/definition/boldness which it didn't with the LCD.

tima
Posts: 78
Joined: Mon Oct 11, 2004 7:18 am

Re: Any non-shimmering LCDs?

Post by tima » Tue Aug 10, 2010 11:03 am

My NEC 20WMGX2 does not do this. It's an S-IPS panel, though.

edh
Posts: 1618
Joined: Mon Mar 17, 2008 1:49 pm
Location: UK

Re: Any non-shimmering LCDs?

Post by edh » Tue Aug 10, 2010 12:37 pm

tima wrote:My NEC 20WMGX2 does not do this. It's an S-IPS panel, though.
IPS screens will always beat cheap TN units. Although prices on screens has come down over the years, a quality monitor still costs a lot more than a basic one and the quality of the basic ones is being squeezed all of the time. I supply a lot of NEC LCD2190UXi's through work and they are very good, but then if you're spending a six figure sum on a system, you expect a good screen (or 4) and don't mind spending £700 on each. I also use some HP LP2475W's through work and they're good but not up to the level of the NECs but then they are only £450.

Looking at that Benq, it is fairly cheap and that generally means it's not aimed at people who care for image quality.

My 2 and a half year old Samsung SM245B doesn't suffer from this kind of effect and isn't too expensive for a screen. £250 should get you something OK for 24".

If a screen doesn't have a DVI input and an ISO mount height, tilt, swivel and rotate base, I wouldn't buy it. It can't possibly be aimed at anyone interested in image quality.

Cerb
Posts: 391
Joined: Tue Apr 13, 2004 6:36 pm
Location: GA (US)

Post by Cerb » Tue Aug 10, 2010 1:27 pm

in that it would lose it's definition, perhaps becoming a bit fainter momentarily, which made me lose focus a bit
That would be ghosting. All LCD monitors do it, but modern non-MVA panels, at least that aren't crap, can be fast enough that the human eye cannot detect it. It absolutely is worth returning a monitor over.

A good TN will be cheaper than a IPS, and should be free of such issues. However, they can still be much more expensive. In the US, we can get crap 24" for under $200, while good ones can still command over $300, without moving from TN. Finding the one in the middle that's not too expensive, but will look good to you...*sigh* that's still a PITA, these days. Samsung, HP, and Viewsonic are some to look at, though.

Cryoburner
Posts: 160
Joined: Sat Dec 01, 2007 4:25 am

Post by Cryoburner » Tue Aug 10, 2010 11:35 pm

Yeah, ghosting issues are caused by the response time of the LCD panel being too slow. Basically, it takes a certain amount of time for a pixel on the screen to change from one color to the next. During the short interval between colors, it will appear as a mix of the two. This is most evident with black objects moving across a white background, or vice verse, since the brightness level needs to change from one extreme to the next, and will therefore take longer to do so.

Ideally, the rating you would look for to avoid this would be the response time shown in a monitor's specifications. A lower rating, like 2ms, should be better than a higher rating, like 5ms, since it implies that the screen can change brightness levels of pixels faster. Unfortunately, there are multiple ways this can be tested, so the rating from one manufacturer or product line might vary from the next. The response times for most screens are measured as 'grey to grey' times, which aren't particularly useful for determining how fast the screen can change from black to white, which is what you encounter when scrolling text. More expensive screens may list both a GTG time as well as a full white to black time.

In any case, to find whether a monitor provides good response times between white and black, you'll typically have to either test the screen yourself, or find reviews at sites that independently test monitor specifications, like TFT Central. User reviews probably aren't all that reliable for this, though if someone mentions excessive ghosting, that probably means there is.

Luke M
Posts: 169
Joined: Tue Jun 08, 2010 4:09 pm
Location: here

Post by Luke M » Wed Aug 11, 2010 1:50 pm

LCDs will never look as good as CRTs when motion (especially smooth scrolling) is involved. 120Hz should help but it isn't a common feature yet.

ntavlas
Posts: 811
Joined: Mon Jul 16, 2007 2:35 pm
Location: Greece
Contact:

Post by ntavlas » Wed Aug 11, 2010 2:18 pm

While ips panels have better overall image quality, a fast tn panel would be your best bet to minimize ghosting when scrolling text though there will still be a peceivable difference when compared to a crt. However, scrolling text is a worst case scenario, in moving pictures/games the difference is less pronounced.

I haven`t experienced a 120hz panel yet but I`ve heard good things about them. The higher refresh rate should also help with tearing, contributing to smoother motion.

doveman
Posts: 866
Joined: Mon Jan 29, 2007 10:30 am
Location: London

Post by doveman » Fri Aug 13, 2010 3:22 am

It's confusing because I understood that IPS panels have higher response times than TN ones, so are more likely to have this problem if that's what causes it. I can only guess that an IPS panel with a 5ms response time might have a better BTW/WTB time than a TN panel with a 5ms response time. Or else IPS panel users just accept this problem as a tradeoff for the other benefits.

That Benq did have a DVI input but wasn't height adjustable, like most of the lower-price TN screens. I'd rather pay an extra £100 or so for a monitor that doesn't give me headaches though, so I'd welcome suggestions for current monitors. Scrolling text might be a worst case scenario, but it's what I (and I would say most other people) use a monitor for most of the time, so I need it to be able to do it properly.

I'm not interested in 3D particularly, but the 120hz monitor I was considering did have 2ms response rate, so it's possibly worth looking at further, although the consensus seems to be that the refresh rate is nothing to do with the problem I experienced, so I'd probably be better off saving a bit of money by getting a good 60hz one.

ntavlas
Posts: 811
Joined: Mon Jul 16, 2007 2:35 pm
Location: Greece
Contact:

Post by ntavlas » Fri Aug 13, 2010 1:59 pm

There are lcd monitors with and without tech that improves the response time of liquid crystals. TN panels with this tech are usually rated at 2ms those without at 5ms. The same applies to ips panels only the ratings are different: usually 5-8ms for those with motion compensation tech, 12-15ms for those without. So, this explains why your 5ms tn panel is relatively slow. Now, while tn panels are slightly faster than their ips counterparts, an ips panel with motion compensation tech will be much faster than a tn panel without. Try one in practice and see how it suits you. You also need to take those rating with a grain of salt. As Cryoburner mentioned, they are not very representative of real world performance though panels with the same rating are usually comparable (reason explained above). In practice a fast tn panel will take 5-8ms on average and as long as 16ms to switch. Slower panels can take as long as 13-16ms on average. Finally, I recommend to check out x-bit`s monitor reviews. While they don`t have that many of them reviewed, their response time graphs are very informative.

Luke M
Posts: 169
Joined: Tue Jun 08, 2010 4:09 pm
Location: here

Post by Luke M » Fri Aug 13, 2010 7:55 pm

doveman wrote:It's confusing because I understood that IPS panels have higher response times than TN ones, so are more likely to have this problem if that's what causes it. I can only guess that an IPS panel with a 5ms response time might have a better BTW/WTB time than a TN panel with a 5ms response time. Or else IPS panel users just accept this problem as a tradeoff for the other benefits.
Response time is a marketing game. If you look at the review test photos on http://tftcentral.co.uk , you will notice that different LCDs can perform quite similarly despite enormous differences in advertised response time.

doveman
Posts: 866
Joined: Mon Jan 29, 2007 10:30 am
Location: London

Post by doveman » Sat Aug 14, 2010 5:15 am

Thanks for the advice and links.

I was interested to see in the review of the Samsung SM2233RZ on tftcentral http://www.tftcentral.co.uk/reviews/samsung_2233rz.htm that, in 120hz mode they found "The difference was quite pronounced, with an obvious improvement in motion smoothness detectable, even in Windows applications. Movement of the mouse and browser windows seemed more smooth for a start."

I realise lack of smoothness was not the cause of the problem I experienced with the Benq, but I'd still be interested in looking at a 120hz monitor, provided it has a good enough response time to eliminate said problem, in order to enjoy the benefits of 120hz mode as well.

Unfortunately, that Samsung fails on several levels for me, not least only supporting 1680x1050, so I'll have to keep looking.

NeilBlanchard
Moderator
Posts: 7681
Joined: Mon Dec 09, 2002 7:11 pm
Location: Maynard, MA, Eaarth
Contact:

Post by NeilBlanchard » Sat Aug 14, 2010 1:46 pm

The iMac displays do not do this "shimmering".

doveman
Posts: 866
Joined: Mon Jan 29, 2007 10:30 am
Location: London

Post by doveman » Sat Aug 14, 2010 5:32 pm


Post Reply