Author Topic: Acer XF240H Review & Viewsonic XG2402 Review: 144hz 1080p Matte TN Panels with AMD-Free-Sync  (Read 12295 times)

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Please support my work via crypto currencies or Paypal (paypal email is thedeepinthesky@yahoo.com).  NCX's Amazon wish list

BTC address:
Spoiler (hover to show)

ETH address:
Spoiler (hover to show)

LTC address:
Spoiler (hover to show)
144hz Washout: Not Vegas

DSC_0051 by Deepinthesky Teslastorm, on Flickr


Acer XF240H product page and Viewsonic XG2402 product pageAMD Free-Sync Compatible GPU List.

Review Information and Methodology:
Spoiler (hover to show)

Viewsonic XG4202 Reviews

Measurements by Magical Chicken (significantly more accurate than the unit I tested)
Review by NCX
Review by PC Monitors
Review by Rtings
« Last Edit: March 28, 2019, 06:31:54 pm by NCX »

Share on Facebook Share on Twitter



NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Features & Stand
« Reply #2 on: August 10, 2018, 01:43:34 am »
Features & Stand

Acer XF240H by Deepinthesky Teslastorm, on Flickr

The Acer XF240H supports AMD Free-Sync (Displayport only; 48-144hz range), come with fully adjustable stand, and is made of sturdy matte plastic which while not a dust magnet, can be stained by cheeto fingers and Monster Zero Ultra.  The Acer's plastic bezel is a medium shade of grey which vastly increases the perceived black depth compared to a fake frame-less casings inner black bezel, and glossy black bezels.  The Acer has Displayport (Free-Sync + 144hz support), Dual-Link DVI (120z support), HDMI (60hz support), 2w speakers and a 3.5mm Audio In and Out ports.  Cables for all of the connections are included, and the monitor does not have an external power supply.  I did not see any obvious build quality or adjustment flaws, or find issues with the buttons, or the Menu system which is simple to use, as well as responds quickly.


PC Monitors Review features a more detailed analysis of the build quality, including adjustment measurements.

The Viewsonic XG2402 supports AMD Free-Sync (Displayport only; 48-144hz range), comes with a fully adjustable stand, and is made of sturdy matte black plastic which is also not immune to greasy finger and energy drink stains.  The XG2401 is a downgrade bezel wise versus the XG2401 since the XG2402's black bezel reduces the perceived black depth or contrast compared to the Acer XF240H and Viewsonic XG2401's medium grey bezels.  The Viewsonic has Displayport (Free-Sync + 144hz support), HDMI 1.4 (60hz), HDMI 2.0 (144hz support), 2x2w speakers, a 3.5mm Audio and 2x USB 3.0.  I did find any build quality issues, but the bezel came dirty, and the Menu system is filled with duplicate settings in different menus, as well as poorly organized.
« Last Edit: October 16, 2018, 06:13:31 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Acer XF240H Menu
« Reply #3 on: August 10, 2018, 01:43:56 am »
Acer XF240H Menu

I sourced the menu photos from the official Acer XF240H manual (available online) since I did not take photos.  There's only three important settings to change, and they are the Brightness, Black Level and Gamma settings, and the Black Level and Gamma settings only need to be changed when the refresh rate is set to 144hz since the XF240H suffers from a significant gamma drop resulting in washed out colors at 144hz versus 60hz.  There's no need to change any other settings unless using a colorimeter to calibrate the monitor, or if wanting to use the gaming gimmicks such as the cross hairs. 

The Brightness (preset to 80=very bright 295.7cdm/2), and Black Level setting are in the Picture Menu:

Spoiler (hover to show)

The Gamma and Color (Red, Green and Blue) controls are in the Color Menu>Colour Temp sub menu which must be switched to User to access.

Spoiler (hover to show)

There's also a 1:1 pixel mapping setting in the Setting>Wide Mode sub menu which must be selected manually since the Full mode is the default:

Spoiler (hover to show)
« Last Edit: October 16, 2018, 06:14:52 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Viewsonic XG2402 Menu
« Reply #4 on: August 10, 2018, 01:45:56 am »
Viewsonic XG2402 Menu

Viewsonic XG2402 Menu Album

Only the most important Menu photos will be posted here; click on the Viewsonic XG2402 Menu Album linked to see photos of every XG2402 menu.

The Text Color preset in the View Mode menu provides the best preset color accuracy out of the box at both 60 and 144hz:

Spoiler (hover to show)

The overdrive or pixel response time setting named Rampage Response is only avaliable in the Gaming Settings>Rampage Response sub menu, and is preset to Faster which causes obvious color streaking and a bit of smearing, and needs to be set to the Ultra Fast setting to get top tier overdrive performance out of the XG2402 at both 60 and 144hz:

Spoiler (hover to show)

At 144hz the Gamma setting should be set to 2.4 in the Display>Color Adjust>Gamma sub menu:

Spoiler (hover to show)

Or in the Gaming Settings>CUSTOM 1, 2 or 3 (CUSTOM 1 and CUSTOM 2 are renamed to 144 and 60 in my photos)>Color Adjust> Gamma sub menu:

Spoiler (hover to show)

The Black Stabilization setting which affects the gamma (brightness and darkness of colors and shades) is in the Display>Color Adjust>Black Stabilization Menu.

Spoiler (hover to show)

The Gaming Settings Menu contains three CUSTOM settings menu which allow one to create three sets of custom settings, and access most of the important settings in the sub menu.

Spoiler (hover to show)

The Black Stabilization setting is also available in the Gaming Settings>Custom 1-3>Black Stabilization Menu.

Spoiler (hover to show)

I renamed CUSTOM 1 144 for 144hz settings and CUSTOM 2 for 60hz settings for consoles:

Spoiler (hover to show)

Unfortunately the color (Red Green and Blue) settings are not accessible through any of the Gaming Settings CUSTOM sub menus.  One must go into the Display>Color Temperature>Full Color Control sub menu to access and adjust the Red, Green and Blue color channel settings.

Spoiler (hover to show)

There's a 1:1 pixel mapping and Aspect ratio scaling feature in the Display>Image Adjust>View Scale Menu:

Spoiler (hover to show)

And the same settings are located in the Gaming>Custom (renamed to 144 and 60 in my menu photos) > ViewScale menu:

Spoiler (hover to show)
« Last Edit: October 16, 2018, 06:18:22 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Flicker/PWM Dimming
« Reply #5 on: August 10, 2018, 01:46:18 am »
Flicker/PWM Dimming

DSC_0041 by Deepinthesky Teslastorm, on Flickr

I use the Test UFO Blu/PWM Trail test to check for PWM from 0-100% brightness.  Both monitors are LED PWM Dimming or Flicker Free as advertised, or use a high enough PWM frequency (20khz) only detectable by an oscilloscope.
« Last Edit: October 16, 2018, 06:19:00 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Brightness & Contrast
« Reply #6 on: August 10, 2018, 01:46:44 am »

The Acer XF240H has a 38.9-341.4cdm/2 brightness range, and a 1000:1 contrast ratio at both 60 and 144hz.  The Acer is dim (38.97cdm/2) enough for use in light-less rooms at 0% brightness (0/100 in the menu), and bright (341.48cdm/2) enough for use in open, brightly lit office rooms, as well as is slightly brighter than the Viewsonic.  The Viewsonic has 100:1 lower contrast, a slightly lower maximum (303.33cdm/2) brightness, and is twice as bright (78.63cd,m/2) as the Acer at 0% menu brightness, but is still dim enough to be used in light-less rooms.
« Last Edit: September 28, 2018, 07:37:00 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Matte Coating
« Reply #7 on: August 10, 2018, 01:47:20 am »
Matte Coating

DSC_0699 by Deepinthesky Teslastorm, on Flickr

Both monitors use the same matte coating which appears a bit dull, grainy and sparkly when viewing white and some light colors such as the light blue sky and white clouds on the Overwatch map illios.  Matte TN 1080p AUO TN panel coatings are obviously grainier than the matte coatings most AHVA/IPS/PLS panels made after 2013 use, as well as dull the vibrancy a bit, but are not as grainy as the matte coatings the non-Dell 24 and 27" 2560x1440 AUO TN panels use.  Glare and reflections are barely noticeable unless very bright room lighting is, and the coatings both monitors use exhibit less hazy white glare under bright lighting than semi-glossy and most matte AHVA/IPS/PLS panels.
« Last Edit: October 16, 2018, 06:20:43 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Excellent For Shooting
« Reply #8 on: August 10, 2018, 01:47:42 am »
Ghosting/Overdrive Performance

DSC_0050 by Deepinthesky Teslastorm, on Flickr

The Acer XF240H's pixel response times are controlled by the OD (overdrive) setting in the Settings Menu while the Viewsonic XG2402's are controlled by the Rampage Response setting in the Gaming Settings>Custom 1, 2 and 3 (I renamed 1 to 144 for 144hz settings and 60 for 60hz)>Rampage Response sub menu.  The photo comparisons are non-pursuit photos of the Test UFO Ghosting test made by Blur Busters creator Mark Rejhon.

Acer XF240H Test UFO Ghost Test
Spoiler (hover to show)

Test UFO Ghosting Test

Viewsonic XG2402 Test UFO Ghost Test
Spoiler (hover to show)

Test UFO Ghosting Test

The Acer's default overdrive setting named OD: Normal setting is the best while the Viewsonic needs to have the Rampage Response setting increased from Fast to Ultra Fast in the Gaming Settings>CUSTOM 1-3>Rampage Response sub-menu.  The higher OD Extreme (XF240H) and Fastest (XG2402) overdrive settings make both monitors suffer from obvious overshoot ghosting (bright, colored and dark transparent glow on certain moving color and shade transitions), and should not be used.  Both monitors offer very similar pixel response times, but the Acer suffers from slightly less overshoot than the Viewsonic, though the differences are extremely minimal, and both monitors offer excellent overdrive for nearly color streaking and overshoot ghosting free gaming experiences at both 60 (important for console gaming) and 144hz. 

The Acer XF240H and Viewsonic XG2402 offer balanced overdrive which I can not find faults with, nor can think of a 144hz display with superior performance, though it is still important to keep in mind that LCD sample and hold motion blur is unavoidable without back-light strobing, a feature which neither monitor has, as well as has draw backs such as cross-talk ghosting and brightness reduction.   


The Acer XB321HK has top tier overdrive performance for a 60hz AHVA/IPS/PLS panel, as does the BenQ Zowie RL2460 in the 60hz TN panel performance category.  The XB321HK is completely free from overshoot, but the secondary ghosting trail is a bit more pronounced due to the AHVA panels slower pixel response times.  The BenQ RL2460's ghosting and overshoot trails captured by my camera are also slightly more pronounced than the other TN panels, but they can still be considered excellent, especially since the perceptual differences between all of these monitors is extremely minimal when gaming.

Also remember that this top tier TN panel overdrive performance comes at a significant loss in image quality since TN panels colors are uneven from top to bottom (vertical gamma shift; TN panels bottom halves are washed out while the top quarter is too dark), and have very restrictive viewing angles.  144hz monitors with slower pixel response times and less balanced overdrive (overshoot ghosting) like the VA panel using Samsung C24FG73 (video review by Lims Cave) offer more even, accurate and vibrant color and shade performance, as well as far less limiting viewing angles.
« Last Edit: October 16, 2018, 06:33:56 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Fast
« Reply #9 on: August 10, 2018, 01:48:04 am »
Input Lag

DSC_0054 by Deepinthesky Teslastorm, on Flickr

Both the Acer XF240H and Viewsonic XG2402 can be considered delay free (<3ms top screen Leo Bodnar measurement), but this is not surprising since most 1080p monitors are, especially gaming oriented TN panels. Usually only multi-input 1440p-4k monitors have around a frame (16.7ms) or two (33.33ms) of input lag.  The actual signal delay (input lag without including the pixel response times) is likely less than a millisecond, but an oscilloscope is required to obtain the "true" value.
« Last Edit: October 16, 2018, 06:35:30 pm by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Inspecting The Wounded
« Reply #10 on: August 10, 2018, 02:03:10 am »
Preset Color Accuracy

DSC_0031 by Deepinthesky Teslastorm, on Flickr

Both monitors suffer from contrast, gamma and black uniformity loss at 144hz versus 60hz, and both monitors need to use different gamma settings to raise the gamma at 144hz to prevent them from looking washed out.  I also tested two inputs for each monitor, those being Displayport (assuming PC use @144hz) and HDMI (assuming console use @60hz).  The Acer's preset color accuracy is slightly different while the Viewsonic's Displayport and HDMI offer the same preset color accuracy.

In all HCFR colorimeter measurement comparisons below the following applies:

Top Left=Acer XF240H 60hz Default                                                                      Bottom Left=Viewsonic XG2402 60hz Default
Middle Top=Acer XF240H 144hz Default                                                                Middle Bottom=Viewsonic XG2402 144hz Default
Top Right=Acer XF240H 144hz with Gamma setting fix                                         Bottom Right=Viewsonid XG2402 Gamma and RGB Level Fix

The Acer XF240H is cable of providing accurate results at 144hz when the Gamma setting is changed from 2.2 to 2.4, and the Black Level setting is changed from 5 to 4.

The Viewsonic XG2402 is capable of providing accurate results by switching the color temperature to User and the ViewMode to Text.

I try to get display gamma to match closest to whichever standard they're preset closest to, which is usually either sRGB (non-linear gamma) or HDTV/REC 709 (linear 2.2 gamma).  The Acer comes closer to HDTV while the Viewsonic is closer to matching sRGB gamma.
 
HCFR Grey Scale Delta E Averages
Spoiler (hover to show)

At 60hz the average color error (Delta E) of both monitors is higher than at 144hz, and the RGB balance is also different.  The Acer is more accurate without changing any settings, however its gamma is significantly worse at 144hz since gamma averages at 1.74 which is very low and results in a very washed out image.  The XG2402 is a bit better with its 2.02 gamma average, but its gamma curved is skewed which results in dark colors and greys looking washed out, bright colors and greys to be to dark.

HCFR Gamma Measurements
Spoiler (hover to show)

As expected, both monitors suffer from gamma drops the higher the refresh rate goes above 60hz.  At 60hz the Viewsonic offers a non-linear gamma curve similar to that of the sRGB standard while the Acer's gamma is more linear, but too high resulting in a bit of black crush, as well as makes bright grey and some bright colors become slightly to dark, but not as dark as the Viewsonic.

As mentioned above, at 144hz the Viewsonic easily bests the Acer's gamma which is far too low, though both monitors look washed out and dull.  Changing two different settings on both monitors provides the best results both are capable of, however the Acer is clearly superior since its gamma is more linear and its two gamma settings allow for more precise adjustment. 

The only way to prevent dark greys and some colors from being washed on the XG2402 is to also put up with 20-100% white (medium to bright greys and colors) being too dark, dulled, and to deal with a bit of detail loss do to the darkening and blending of colors and grey shades.  The XF240H's gamma remains slightly U-Shaped, but it can be raised and lowered according to preference.  10% white (dark grey) at 2.3 is slightly too high, but lowering the gamma causes 30-70% white to drop to 2.0, which results in some colors and shades to be obviously washed out.

HCFR RGB Measurements
Spoiler (hover to show)

The XG2402's RGB Levels are poor, quite skewed and require calibration with a colorimeter and an ICC profile to fix while the Acer is a bit more accurate since the RGB levels are more balanced and linear.  I was unable to improve either monitor significantly by adjusting their Red, Green and Blue settings in the menu, and had to rely on the ICC profile created by dispcalgui program and my Spectracal C6 HDR2000 colorimeter.   

HCFR Color Temperature Measurements
Spoiler (hover to show)

HCFR Color Space Measurements
Spoiler (hover to show)

The XG2402 can fully cover both the sRGB and HDTV/REC 709 color space, and only slightly over-saturates greens, yellows and oranges while the Acer XF240H falls short in the top left (dark blues and greens) and over-extends significantly more on the right side of the triangle.  Since the over and under-saturation differences are slight the difference between the two monitors is slim, and calibration is required to take advantage of the Viewsonic's superior color space coverage since the preset gamma is so skewed and makes light colors and greys to dark and dulled.

Standard and Custom 1 Measurements by colorimeter owning forum member MagicalChicken.  His XG2402 was significantly more accurate than the unit I tested, but has very similar gamma and RGB.


The Acer XF240H offers great preset color accuracy at 60hz which I can't really criticize when considering the low price.  The Acer is very accurate and free from an obvious preset color dominance while the Viewsonic XG2402 is too blue and has both skewed and inaccurate gamma and RGB levels which can not be normalized without an ICC profile.  When switched to 144hz the Acer suffers from a significant gamma drop and looks significantly more washed out than the XG2402, but the RGB color balance remains vastly superior, and it's possible to achieve mostly accurate gamma from the Acer at 144hz by changing the Black Level setting from 5 to 3, and gamma from 2.2 to 2.4.  The XG2402 also requires two different settings to be changed, those being the Black Stabilization setting from 11 to 9, and Gamma setting from 2.2 to 2.4.

Regardless of which settings are used the Viewsonic's gamma is way too high in the 50-100% white section resulting in many light colors and shades to be too dark and a bit dull while dark colors and shades are a bit washed out.  The Acer's gamma is more linear, and way too low at 144hz, but significantly superior after changing the Black Level and Gamma settings.  The Acer also barely benefits from an ICC profile while the Viewsonic needs one to offer good results for a TN panel.

Banding

AUO TN panels tend to suffer from very obvious and frankly horrific banding when viewing
and this 60fps Westworld trailer.  Here's the Dell S2417DG/S2716DG banding example from a reddit user, and here's the
(top screen).  The post with the Westworld example was not made until long after I sent both monitors back, but I did try the Dawn Engine image on the Viewsonic XG2402 which suffered from the same horrific banding as the Dells.  It's safe to assume that the Acer XF240H also suffers from the same banding since both use TN panels made by AUO.  Both monitors suffered from obvious banding in mostly black filled content or very dark scenes, especially when viewing content on YouTube.  I did not notice banding in any of the dark game (Destiny, Dying Light, The Order 1886) screen shots I display on every monitor I test, or in the games I tried, but there's no denying that banding is a very obvious issue when viewing specific types of content, and is probably going to remain an unavoidable issue among AUO TN panels for some time.  Calibration did not help reduce the banding.

I also checked for banding on my Acer G257HU (1440p IPS), custom glossy 27" 1440p (IPS), Dell S2719DGF (1440p TN),  HP 25es (1080p IPS), Qnix UHD32R (4K AHVA), X-Star DP2710 (1440p PLS) and Viewsonic VP2780-4K (4K IPS).  Only the custom glossy 27" 1440p (IPS) suffered from noticeable banding (increased banding with the ICC profile active) while the rest suffered negligible amounts unless I stretch the 1440p Dawn Engine image out and look closely at what appears to be a sun glint at the center of the crescent arc or moon.

Reddit Posts with banding:
from r/Monitors

from r/Monitors

« Last Edit: January 29, 2019, 02:07:48 am by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
The Wheat Is Taller On The Other Side Of The Fence
« Reply #11 on: August 10, 2018, 02:03:31 am »

The XG2402 greatly benefits from an ICC profile created by calibration software dispcalgui and my Spectracal C6 HDR 2000 colorimeter while the XF240H does not, though it dos need to have its gamma settings changed to counter the 144hz "AUO wash out" effect, which is loss of contrast, gamma and uniformity 144hz AUO TN panels suffer from when set to 144hz.  The XG2402's color balance, particularly the Blue levels is skewed and way too high in the 0-40% white range resulting in a blue dominance which requires software calibration created ICC profile to correct.  An ICC profile is also required to correct the skewed native gamma which is way too high in the 40-100% white range which results in many light colors being too dark, dulled a bit, as well as for shades to blend which results in a loss of detail.  The XG2402 offers slightly higher sRGB and REC 709 color space coverage, but dark greys are a bit more blue than the XF240H which nullifies the slight color space coverage superiority. 

After calibration the main difference between the two is mainly perceptual since the XF240H has a perceived black depth increasing grey bezel versus the XG2402's black bezel, and XF240H I tested also has better uniformity, especially in dark scenes, though this could be due to panel lottery.  Both panels viewing angles are the same, and vertical gamma shift is equally as obvious, and their viewing angles are equally as restrictive, and prevent one from being able to lean back or raise either monitor.  In order to get the best viewing experience one must look down at TN panels from above, and ensure that the top of the TN panel lines up with the tip of the viewers nose, or slightly below the eye line like so:

Spoiler (hover to show)

Discounting the typical TN panel flaws (restrictive viewing angles and vertical gamma shift or uneven color from top to bottom) neither monitor can be considered good for a TN panel since the bottom quarter of the panels clearly have lower contrast and worse uniformity compared to the first generation of CCFL back-lit TN panels from 2010-2011 like the Asus VG236H (glossy), PLanar SA2311W (matte) and Samsung S23A750D (glossy) which used TN panels made by LG and Samsung.  The AUO TN panels the Acer and Viewsonic use are better than those used by the Asus MG248Q and the first few years of LED back-lit AUO TN panels, but are still not up to par with the final generation of CCFL back-lit TN panels made by LG and Samsung, both of which sold both glossy and matte 120hz TN panels.
« Last Edit: October 17, 2018, 12:10:16 am by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Calibration & Refresh Rate Comparison 1: Uncharted 4
« Reply #12 on: August 10, 2018, 02:03:49 am »
Calibration & Refresh Rate Comparison 1:
Uncharted 4

To properly compare the photos right click on the photos and closely inspect larger versions in a new tab, especially if experience trouble with the spoiler pop downs. Menu calibration refers to my use of a colorimeter and calibration program to increase the color accuracy as much as possible using only the monitors menu settings.

Acer XF240H 60hz Menu Calibrated
Spoiler (hover to show)

Acer XF240H 144hz Un-Calibrated
Spoiler (hover to show)

Acer XF240H 144hz Menu Calibrated
Spoiler (hover to show)

Viewsonic XG2402 60hz Un-Calibrated
Spoiler (hover to show)

Viewsonic XG2402 60hz Menu Calibrated
Spoiler (hover to show)

Viewsonic XG2402 144hz Un-Calibrated
Spoiler (hover to show)

Viewsonic XG2402 144hz Menu Calibrated
Spoiler (hover to show)

Viewsonic XG2402 144hz Calibrated with ICC Profile
Spoiler (hover to show)
« Last Edit: October 17, 2018, 01:08:59 am by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Calibration & Refresh Rate Comparison 2: Overwatch
« Reply #13 on: August 10, 2018, 02:04:14 am »
Calibration & Refresh Rate Comparison 2:
Overwatch

To properly compare the photos right click on the photos and closely inspect larger versions in a new tab, especially if experience trouble with the spoiler pop downs.  Menu calibration refers to my use of a colorimeter and calibration program to increase the color accuracy as much as possible using only the monitors menu settings.

Acer XF240H 60hz
Spoiler (hover to show)

Acer XF240H 144hz Un-Calibrated
Spoiler (hover to show)

Acer XF240H 144hz Menu Calibrated
Spoiler (hover to show)

Viewsonic XG2402 60hz Un-Calibrated
Spoiler (hover to show)

Viewsonic XG2402 60hz Menu Calibrated
Spoiler (hover to show)

Viewsonic XG2402 144hz Un-Calibrated
Spoiler (hover to show)

Viewsonic XG2402 144hz Menu Calibrated
Spoiler (hover to show)

Viewsonic XG2402 144hz Calibrated with ICC Profile
Spoiler (hover to show)
« Last Edit: October 17, 2018, 01:09:16 am by NCX »

NCX

  • Administrator
  • Hero Member
  • *****
  • Posts: 761
    • View Profile
Back-Light Bleed & Uniformity
« Reply #14 on: August 10, 2018, 02:04:40 am »
Back-Light Bleed & Uniformity

The Acer has slightly higher measured contrast, slightly better black uniformity, and a perceived black depth increasing grey bezel while the XG2402 has a black bezel.  Neither monitor suffers from obvious back-light bleed, but both suffer from obvious contrast loss at 144hz versus 60hz, especially in the bottom quarter of both panels.  The black level rises in the bottom quarter resulting in higher measured black or lower contrast, and perceive-ably worse black depth, though despite being extremely similar, the Acer is noticeably better at all refresh rates. 

The measured and perceived black depth offered by the Acer is superior when my ceiling light (2200 lumen 6500k LED light) is on due to the grey bezel versus the Viewsonic's black bezel, as well as when off since the Acer has slightly higher contrast and better uniformity.  If the opposite were true the Acer would still have better perceived black depth than the Viewsonic when the lights are on since the Acer has a perceived black depth increasing grey bezel like the Viewsonic XG2402's predecessor, the XG2401.

To properly compare the photos right click on the photos and closely inspect larger versions in a new tab, especially if experience trouble with the spoiler pop downs. Menu calibration refers to my using a colorimeter and calibration program to increase the color accuracy as much as possible using only the monitors menu settings.

Acer XF240H 60hz Black
Spoiler (hover to show)

Viewsonic XG2402 60hz Black
Spoiler (hover to show)

Acer XF240H 144hz Black
Spoiler (hover to show)

The Acer suffers from obvious contrast and uniformity loss at 144hz versus 60hz since the preset gamma drops significantly.  The Viewsonic XG2402's gamma barely changes when set to 144hz, and there's not a perceptual difference when viewing black at 144hz before and after calibration, however there is a clear difference in the bottom right corner at 60 and 144hz.

The next two photos are both named gamma fix since I used the menu settings to try and achieve the best gamma for the Acer (switch Black Level from 5 to 3 and Gamma from 2.2 to 2.4) and Viewsonic (switch Gamma from 2.2 to 2.4 and Black Stabilization from 11 to 9).  An ICC  profile is required to obtain truly accurate gamma from both monitors, but the Acer comes much closer to matching a display standard (HDTV/REC 709 with linear 2.2 gamma) while the Viewsonic has a non-linear curve.

Acer XF240H Gamma Fix 144hz Black
Spoiler (hover to show)

Viewsonic XG2402 144hz Gamma Fix Black
Spoiler (hover to show)

It should be obvious that the black level rises (lower contrast) resulting in black looking significantly brighter at 144hz versus 60hz when viewing these photos on a display with semi-accurate gamma.  This is very disappointing, but also normal for 144hz AUO TN panels.  The good 120hz CFFL back-lit TN panels from 2010-2011 made by LG and Samsung did not have this issue, and offered better preset color accuracy than many of the 144hz AUO TN panels.  The black level and uniformity loss are quite obvious unless one has very bright room lighting, as are the the more washed out colors and shades, especially on the Acer which has significantly worse preset gamma at 144hz than he Viewsonic. 

The Viewsonic has three custom modes which one can save use to create three sets of different settings while one must change the gamma settings of the Acer if wanting to use both 60 (console gaming) and 144hz.
« Last Edit: October 17, 2018, 01:00:40 am by NCX »