Problems with BenQ G2420HDBL

doveman

doveman

doveman

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I've just bought one of these Benq LED monitors and I've noticed that the lighting is quite uneven, so that on a completely black screen, there are bands on the left and right of the screen that are noticeably lighter than the centre. This can only really be seen in a very dark room and doesn't photograph very well.

With certain colours, particularly orange and green, I also notice it's darker across the top/top left than the rest of the screen. Is this what I should expect with a £150 LED monitor or should the colour be more uniform?

I've taken some photos but my camera's not great.














 
One of the reasons TN panels are so cheap (compared to IPS screens) are the viewing angles. You sure it's not this? I have the same screen and it can get darker or lighter (as with all TN panels) if you change the angle.
 
I don't think it's this as even if I move my head around, the top stays darker than the rest of the screen, so even if my eyes are directly in line with the top left, whilst it might look a bit lighter than when my eyes are in the centre of the screen, the lower part of the screen remains lighter than the top part.
 
This sounds perfectly normal for a TN LCD panel and it would be particularly noticeable on a fairly large screen. Look at the dark part at the top of your screen and see if it gets lighter if you move your head upwards so it's above the monitor. What do you see if you look at the coloured boxes here? The purple colour in particular should shift to various hues as you move your head around and appear darker at the top. It's perfectly normal for a TN panel.

You could be having a problem with excessive backlight bleed so try your best to photograph the black screen image if you can (I know it's difficult).
 
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I know these monitors have narrow viewing angles and I'd expect the top of the screen to get lighter as I move my head up, and indeed for the whole screen to change colour as I move my head around, but I'd still expect more uniformity when looking dead on at the screen.

You might be right about excessive backlight bleed though, because I notice that with certain colours, as well as the top the bottom corners also look a bit darker/smudged than the rest of the screen.

I'll try and photograph the black screen image again when it's darker as I did notice that about a 1/5th of the screen on both sides was lighter than the center when I first tested it.
 
I've also found that when scrolling a web page the text/page appears to shimmer, most noticeably when holding the mouse button down and dragging the scroll bar slowly or by pressing the arrow keys.

This plays havoc with the eyes and makes it impossible to keep focused on the text. I'll have to look at some other LCDs to see if they also do this, but I wouldn't have thought that it's normal. This happens with both my PCs, one connected to the VGA and the other to the DVI.
 
That is really strange... Can any users of similar BenQ monitors confirm these problems for us? I know there are a fair few who own the G2420HDBL. I know that some LED-backlit monitors are more prone to backlight bleeding issues because they are designed to be so thin that the whole thing can actually be a bit flimsy. I have never had such issues with the XL2370 though (an edge-lit LED from Samsung) but I am getting another sample to review and will have a good look to see if I notice any bleeding issues or text shimmering.
 
OK, I had a chance to look at my Dad's Acer X243HQ LCD over the weekend and that looked much the same, with a full-screen of orange darker at the top then the rest of the screen and flickering of text when scrolling, so I'm not sure now that there is anything wrong with my Benq. If this is normal for LCDs, I'm not sure how people put up with them though!

A good example of the flickering can be seen by looking at stripy shirts when scrolling, such as the ones linked to below.

It's probably easiest to observe by scrolling one step at a time with the up and down arrows. It might be described better as pulsing or strobing.

http://www.debenhams.com/webapp/wcs...01_080010185003_-1?breadcrumb=Home~Men~Shirts

http://www.debenhams.com/webapp/wcs...01_080010151345_-1?breadcrumb=Home~Men~Shirts

http://www.debenhams.com/webapp/wcs...01_080010185080_-1?breadcrumb=Home~Men~Shirts

I'm not sure if this page comes up the same every time, but if it shows a red shirt bottom left, a blue one bottom right and a black one above that, the problem's particularly noticeable as all three pulse. http://www.debenhams.com/men/shirts..._18664_18528_128764_ms}&catalogId=10001&pns=y

I've also noticed that on that page PCM2 pointed me to http://www.lagom.nl/lcd-test/viewing_angle.php when looking at the Lagom text, it turns bright red momentarily whilst scrolling, which isn't mentioned as a common problem on there, so probably shouldn't be happening!

A similar thing happens with the bottom left box on http://www.atrise.com/lutcurve/ above the text "If you see color tones on the image above", which is almost grey but when scrolling the colours come up quite intensely.

Incidentally, I used Lutcurve to calibrate my monitor and found it pretty handy. I didn't use it's controls to calibrate, as then I'd need it loaded all the time, but running the Benq in Standard mode, I got the blacks and whites about right with Brightness and Contrast both at 30.

On the Gamma screen, I couldn't seem to get that right using the Benq's colour controls, so I've left that on Normal and in Catalyst Control Centre, on the Color tab, dropped the Gamma down to 0.75, which gets it pretty close.
 
I don't see any pulsing on your Debenham links, but do see the other effects. Must be common to LCD's, but this is the first one I've owned, so other peeps might be more knowledgeable.
 
Thanks for checking that out for me.

I did say to use the arrows to scroll up and down but it's actually more noticeable on the Debanham's pages if you click and hold on the scroll bar and slowly drag up and down. It's most noticeable on that page with multiple shirts on, so perhaps you could try this for me.

Rather dissapointing if it is the case that all LCDs have this problem where colours appear and disappear and pulse, particularly as no one talks about it. We all know not to expect as deep blacks and as wide viewing angles as with a CRT, but you'd think someone would have warned us about these other problems.

Be interesting to hear from people with other LCDs if they're the same, although our Benq's are probably no worse than most LCDs, unless we've both got faulty ones, which I doubt. But if anyone knows of a LCD that doesn't have these problems and isn't an expensive IPS panel, I'd love to hear about it.
 
It could be that you are particularly sensitive to the lower responsiveness of an LCD compared to a CRT monitor. This is something people get used to so it could just be that you need time adjusting.

What refresh rate were you using on your last CRT? This problem could be alleviated slightly by 120Hz screens, although personally I don't find it an issue on a good responsive 60Hz TN LCD panel. If you look on my website (link if you click my name) an upcoming technology (OLED, organic light emitting diode) is discussed as an eventual replacement for LCD panels. You can also track the latest developments of the technology, which will provide panels that are considerably more responsive than any LCD panel and with beautiful colours. :D
 
You might be right that I'm particularly sensitive, but I don't think that explains greys changing to colour when scrolling!

I was only running at 85hz on my CRT.

I was considering returning this Benq and getting an IPS panel instead, but I'm not sure whether they suffer from the same problems as well. After all, nowhere seems to mention the problems I've found with this LCD/LED monitor, so they might just be ignoring it on IPS panels as well. Guess I'll just have to try and get a look at some and see.

OLEDs look great but probably won't be affordable for another 5 years. Can I put up with the size of a CRT until then? Quite possibly if this is the best that LCDs can manage at the moment.
 
You could do. Depends if you play FPS games competitively as IPS panels have slower response rates then TN. If you're just a casual gamer or do not game at all than an IPS would be great. HP ZR24W or Dell U2410 are some suggestions, but even they do have their flaws.
 
Yeah, I noticed that IPS panels have slower response rates when I was looking at some earlier. I don't game competitively but do like to game, so that might be a problem.

What are the other flaws you had in mind?
 
I very much agree with your estimation of the affordable OLED monitor arriving. Things seem to be picking up pace now and if I'm optimistic I would say that it could be slightly earlier than 5 years time that OLED hits the (almost fully) affordable mainstream.

I haven't used the G2420HDBL myself and you shouldn't look too much into response rates, but it may be that the 5ms G2G response rate of the BenQ and your dad's Acer is holding them back. It's difficult to say because most people won't have a problem with this, but a 120Hz monitor with 2/3ms response rate may be better for you. I'm not sure how you'd test this out though.

As for IPS panels. The issue you have with 'shimmering' would be even more noticeable on any IPS panel. I personally find them acceptable for gaming, but simply not the best option. You will notice that the colour shift you mentioned earlier will be eliminated, which is a plus... When people speak of the "flaws" of the HP ZR24W they are most likely talking about the weak contrast performance and poor black levels. The U2410 is known to be a little hit and miss as some panels have some colour uniformity issues that you really wouldn't expect from an IPS panel - but these may have been cleared up with new screen revisions.
 
Got to say the problems mentioned by the OP are so rare and only happen under particular circumstances, as not to be a concern for me.
My games are getting a new lease of life with this display, which I'm finding utterly superb.
Replaying Mass Effect at full 1920 x 1080, for example, is a visual treat, something I never thought as much when using my CRT.
This monitor has no backlight bleed what so ever, no ghosting, no discernible lag (and I'm picky about things like that).
Highly recommended, especially at the cracking price I got it for.
 
KelticDaz said:
Got to say the problems mentioned by the OP are so rare and only happen under particular circumstances, as not to be a concern for me.
My games are getting a new lease of life with this display, which I'm finding utterly superb.
Replaying Mass Effect at full 1920 x 1080, for example, is a visual treat, something I never thought as much when using my CRT.
This monitor has no backlight bleed what so ever, no ghosting, no discernible lag (and I'm picky about things like that).
Highly recommended, especially at the cracking price I got it for.
Click to expand...

Totally agree with Keltic.

A very uniform lighting alround, no bright edges ( as i had before with my Samsung 243b ), good vibrant colours, a great screen.

Viewing angles are poor, as with all TN panels though, but for the price it is a superb monitor.
 
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