WA104 Projector Lens 0.75:1 for 2 Hualu Models: HL-GU18K, GU21K

WA104 is a short-throw lens for 0.96-inch panels (Hualu), featuring a 0.75:1 throw ratio and lens shift. It is compatible with 2 models across 1 model series. This article presents the lens specifications, installation distances, model compatibility list, and replacement considerations in one place.

I. Lens Specifications

Lens shift is the key differentiator of this lens. The shift range of 21.00% horizontal and 8.20% vertical allows the projector to be installed off the screen centerline and the image repositioned using lens shift without relying on keystone correction. Keystone correction comes at a cost—each correction step sacrifices some effective pixels, causing text edges to blur. In professional installations, never use keystone correction when lens shift can solve the problem; preserving image quality is the bottom line.

II. Calculating Installation Distance from Throw Ratio

The throw ratio is the ratio of the installation distance to the image width. This is a prime lens (0.75:1), so the installation distance varies linearly with image size, leaving no adjustment margin. Accurate measurements are essential before installation.

The values above represent the clear distance from the front of the lens to the screen and do not account for space required for rear housing ventilation and cabling. They are calculated based on a 16:10 aspect ratio; actual values should be confirmed through on-site measurements and the manual.

III. Compatible Models (2 Models, Hualu)

The following table lists the models from newest to oldest by production date, along with the resolution, brightness, and zoom ratio of each model's original standard lens, making it easy to identify the right option for each project.

The zoom ratio is the zoom factor of the model's original standard lens (upper limit of the original throw-ratio range ÷ lower limit), not the zoom range of the lens featured in this article.

Common Characteristics of These Models

The original standard lenses for both models mostly fall within the 1.5~2.0 throw-ratio range. The 0.75:1 ratio of the model featured here effectively changes the focal setting, allowing a different image size from the same projection distance—this is the direct reason for replacing the lens. It also retains full lens-shift capability, so the image can still be aligned after the focal setting is changed.

IV. Three Checks Before Replacement

• The panel and resolution must match. This model is designed for 0.96-inch panels. Projectors with a different panel size or resolution may show differences in projection performance, so checking the nameplate on the projector before installation is the safest approach.
• Check the interface and locking mechanism. Interfaces are generally compatible within the same platform generation, but the positions of the locking tabs vary between generations. If the image appears skewed or the edges look soft after installation, the locking mechanism is usually not fully engaged rather than the lens itself being faulty.
• Account for the lens-shift margin in the installation. The shift range provides some installation flexibility, but image quality at the edges declines when the shift is pushed to its limit. In actual use, keep the shift within 70% of the rated value.

For compatibility with models not listed, it is safer to send us a photo of the projector nameplate and the original lens for verification—platforms of the same generation often share the same interfaces, but ordering solely on the basis of a similar model number carries unnecessary risk.