Author Topic: Acer XF240H Review & Viewsonic XG2402 Review: 144hz 1080p Matte TN Panels with AMD-Free-Sync  (Read 8203 times)

NCX

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Ugly
« Reply #15 on: September 11, 2018, 03:01:53 am »

This vertical gamma shift comparison of the BenQ XL24200G (144hz 6 bit +FRC AUO TN panel with G-Sync), Dell S2716DG (144hz 8 bit AUO TN panel with G-Sync) and a Qnix QX2710 (8 bit overclock-able Samsung PLS panel) I made in 2015 shows how TN panels colors are obviously uneven from top to bottom, even when viewed correctly since the gamma shift is not a result of off angle viewing.  This comparison applies to both the Acer XF240H and Viewsonic XG2402, which are actually a bit worse since neither the BenQ nor Dell suffered from obvious contrast loss in the bottom quarter of the panel, or gamma loss at 144hz versus 60hz.

Both monitors have normal (very restrictive) viewing angles for a TN panel, so forget about viewing either of them on a desk while sitting in bed, leaning back in a desk chair, or with the desk chair lowered.

There is one correct viewing angle, or one correct way to view TN panels, which is from above or while looking down at them.  The below photo compilation is of photos taken for the Asus VG258Q Review by PRAD.  The Acer and Viewsonic's viewing angles are basically identical to the VG258Q's:

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If raised or looked up at TN panels become very dark since their optimal viewing angle is from above while being looked down at.  Even when viewed the correct way, one still has to deal with vertical gamma shift which causes TN panels colors and shades to be darker in the top quarter (black crush if the gamma is 2.2-ish in the center), and washed out in the bottom half of the panel.

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Squares 1-5 are normal in the center area, but become quite dark when moved up since TN panel gamma is much higher in the top quarter of the panel, and can cause black crush if the center gamma is 2.2 or higher:

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In the photo of the XG2402 below one can see how much darker grey is in the top part of the panel, as well as is significantly darker on the sides compared to center bottom the middle:

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« Last Edit: October 17, 2018, 01:53:26 am by NCX »