ViewSonic XG2401 FreeSync Monitor Review
Panel Backlight Bleed
An LCD or LCD LED based monitor relies upon either one or multiple sources of light to illuminate the Liquid Crystals so as to create an image that consumers can see. In a perfect world all the light would either go through the open Crystals or be reflected back into the interior of the display via the closed crystals. Due to manufacturing process most monitors exhibit light leakage around the edges of the monitor. This issue is called Backlight bleed and can drastically lower the contrast near these effected areas. This causes colors to have a ‘washed out’ appearance with blacks appearing to be more gray that black. Optimally a monitor should have zero bleeding, but if the amount is judged to be minor enough we will consider it to be adequate.
To determine the amount – if – any backlight bleed a given samples exhibits we have placed the monitor in a completely dark room, and using a Nikon D810 w/ 24-70 f2.8E VR lens have taken a series of pictures of the monitor. In between each shot the ISO is raised by one stop until a picture is captured that shows the amount of bleed occurring.
Due to variances in lumen output from one model to another we have chosen two actual brightness settings instead of a percentage output. The first is 250cd/m2 which is brighter than most consumers will be comfortable using, and yet any modern monitor is easily capable of producing. As such it represents a realistic, but repeatable, worst case scenario. The second settings is 120cd/m2 which is a setting considered by professionals to be optimal for serious work. As such it will show the amount of backlight bleed at more realistic levels.
This level of backlight bleed is disappointing but not all that unexpected. Inexpensive TN panels have a reputation for being poorly sealed and the XG2401 is no exception. Even at a lowered 120cd/m2 the bleed is noticeable. More importantly, the level of backlight bleed is high enough that it does not take an entirely dark room to notice it as color fidelity and gamma levels are noticeably ‘off’ even under more normal lighting conditions.
The only saving grace is this is not the worst amount of backlight bleed we have ever seen, and for its class the XG2401 is actually fairly average. Simply put if backlight bleed is a major issue for you then your choices in this price range are severely limited.
Gamma correction is one of the hardest terms to explain. However, for our purposes the gamma correction of any electronics device is how bright or dark an image will be displayed on a screen.
All PC devices now use 2.20 gamma as the default. Any variance from this will result in an image being either underexposed which will create black crush and underexposed shadow detail or washed out with too little black level detail (aka being over-exposed).
While 2.20 is the gold standard, a minor deviation of 0.10 will in all likelihood never be noticed by anyone other than professional photographers. Higher levels of deflection however will be noticed by just about everyone.
Much like the XG2401’s default panel uniformity, its default gamma level is quite poor. It is so poor that users will want to adjust it right away. Unfortunately, the On Screen Display options for this aren’t quite up to the task and as such you’ll want to either invest in a colorimeter, or borrow one from a friend. Another option is using software-based tools through driver software to achieve the same, though from an entirely first person viewpoint. We simply cannot recommend anyone using this monitor without first correcting the gamma.