REVIEW: Lenovo L2440p Part 13

For 1080i, things were only slightly better when the analogue connection was used. An option in the graphics driver of the laptop made it possible to force this resolution through, whereby the image content was destroyed in terms of details to the extent that it become unrecognisable. Coarse details are still visible, but this is unacceptable for film playback.

A full screen view of the playback of 1080i via the analogue input can be seen on the left; on the right is an enlarged detail from the same image.

Thus, in this resolution, a HD video source is in no way useful when connected to the analogue input.

This is especially annoying when it is clear to the user that the monitor achieves completely judder-free playback, not only for 60Hz, but also for 50Hz signals. The judder test with which this was tested displays a white band which scrolls across the black screen. If a 50Hz signal is transferred to 60Hz output within the monitor, the movements of this bar are halting and the image output judders.

Even when playing back a 48Hz signal, the L2440p displays an image, but blends in a warning that the monoto5r is being run outside of its specifications. This warning cannot be removed. This is a pity, especially as it obviously functions perfectly judder free and the image output does not suffer. The only thing that is lamentable in the judder test is that the white bar at the side looks slightly frayed in the direction of its movement.

Detail from judder test. The white bar scrolls from left to right across a black background.

Video-Scaling

When a HD video source is used on the HDCP-enabled DVI-D connection, the image is either stretched to full screen or incorrectly compressed when the "correct aspect ratio" is selected. The following test images should demonstrate this behaviour more clearly. Here, the test images show the exact measurements of the 1.920 x 1.080p image when played back via a PS3 using a HDMI to DVI cable.

Left: 1080p Test image at full screen display. Right: the same image with "justified" selected in the OSD.

This test image also shows that no overscan is used and no edges are truncated.

The test picture below shows in an impressive manner how strong the distortion in "justified" mode looks. The white oval should be a perfect circle. Here, two effects are going on at the same time: First, the image is stretched to a height of 1,200 pixels and then it is compressed towards the sides.

Strongly distorted image for "justified" display.

Users who can look past the slight distortions which arise in normal full screen mode will receive absolutely good image quality. The interpolation losses which arise at 1.920 x 1.080 are not as bad as those in other resolutions and are not noticeable at all for moving pictures. Only in darker scenes does it continue to hold true that some of the darkest image details are lost. However, this does not spoil the fun in scenes with a lot of motion or action.

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