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GeChic On-Lap 2501M 15.6" Battery-Powered Monitor, Tested

Results: Stock Brightness And Contrast

Since the On-Lap 2501M is a twisted-nematic (TN) panel, we’re using some comparison data from past reviews of 23- and 24-inch TN-based panels. We're also including data from the last four screens we tested, all of which are 27-inch IPS monitors.

With its brightness control set to maximum, the On-Lap comes up a tick shy of the 200 nit mark. For a monitor that will likely be used in bright environments, we would like to see a little more light output.

The max black level falls just below the middle of our pack. However, 0.4625 cd/m2 isn’t a bad result. In fact, in a high-ambient light environment, this will serve to keep shadow detail visible.

Contrast ratio is the most important factor concerning the perceived depth and dimensionality of the image. The greater the ratio, or dynamic range, the more three-dimensional the picture will appear.

The max contrast ratio is toward the bottom of the pack; a little more light output would help improve this number.

Turning down the brightness control all the way generates some very low numbers for both maximum white and minimum black.

At just over 17 cd/m2, the image is far too dim to be of any use, even in a blacked-out environment. We recommend setting the brightness to no lower than 25. At that level, the white luminance increases to around 45 cd/m2.

On the plus side, bottoming out the brightness slider produces a very impressive black level. Thanks to the On-Lap’s excellent gamma tracking, shadow detail is maintained even at this low reading.

Again, minimizing the brightness produces an image that is not practical for normal use. With the brightness control on 25, the black level is still less than 0.1 cd/m2, which puts it in fourth place.

The minimum stock contrast ratio is pretty much unaffected by the position of the brightness slider. No matter where it’s set, the ratio lands between 420: and 430:1.

Contrast performance is not a strong suit of any LCD panel, regardless of the technology it employs. While this metric has improved over the last few years, it’s still behind other display technologies, such as plasma. And alas, the tremendous dynamic range of our dearly departed CRT monitors may not be equaled until OLED panels become more viable.

Christian Eberle
Christian Eberle is a Contributing Editor for Tom's Hardware US. He's a veteran reviewer of A/V equipment, specializing in monitors.