Author Topic: Acer XF240H Review & Viewsonic XG2402 Review: 144hz 1080p Matte TN Panels with AMD-Free-Sync  (Read 7947 times)

NCX

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Back-Light Bleed & Uniformity
« 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
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Viewsonic XG2402 60hz Black
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Acer XF240H 144hz Black
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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
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Viewsonic XG2402 144hz Gamma Fix Black
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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 »