BenQ LS1ST2 Ultra Wide Zoom Short-Throw Projector Lens Review: LU9915 Compatibility

BenQ Genuine Lens LS1ST2 Ultra Wide Zoom is a genuine optical accessory for BenQ engineering projectors. It is a Short Throw lens with a throw ratio of 0.75:1 - 0.93:1. The factory compatibility list covers 1 model, so simply verify the projector model and panel size before installation—no adapter rings are needed. The value of a genuine lens lies not in a few extra rows of specifications, but in its factory calibration to the optical path and mount of that projector series. Once installed, the image circle, edge illumination, and focusing travel all match the design values, so there is no need to use keystone correction to compensate for image quality.

I. Lens Specifications

The above specifications are subject to the factory specifications. For mechanical dimensions, flange distance, and mount type not shown in the specifications table, contact us with the projector model for verification. Ordering based solely on a similar model carries the risk that the lens will not fit.

II. Converting Throw Ratio into Installation Distance

The throw ratio is the ratio of the installation distance to the image width. This genuine lens has a zoom function (0.75:1 - 0.93:1), so each image size corresponds to a range of installation distances. The lens can focus at any point within that range during installation.

These distances represent the clear distance from the front surface of the lens to the screen and do not include space behind the projector for cooling and cable connections. They are calculated for a 16:10 image, with actual distances subject to on-site measurement and the manufacturer's manual.

Image quality differs at the two ends of the zoom range: near the close end, the image is brighter and the edges are slightly softer; near the long end, the edges are sharper and brightness is slightly lower. Where site conditions permit, use the middle of the range. After installation, first find the sharpest setting on the focus ring, then fine-tune the lens shift.

III. Compatible Models (1 Model)

The table below is taken from the factory compatibility list. Brightness and resolution are populated from the model database; entries that cannot be verified are marked with “—” rather than guessed.

To check whether a model not on the list is compatible, send us photos of the projector nameplate and current lens. Projector platforms from the same generation often share the same mount, but ordering based on a similar model is not worth the risk.

Throw Ratios for Different Model Series

The nominal throw ratio varies by series when the same LS1ST2 Ultra Wide Zoom lens is installed on the following series. Select the value based on the series of the actual projector.

IV. Three Checks Before Replacement

• Confirm the projector chip and resolution. Genuine lenses are designed for a specific panel size. If the panel specifications differ, the image circle cannot cover the full image, resulting in vignetting or edge light loss after installation.
• Calculate the installation distance first. This lens has a nominal throw ratio of 0.75:1 - 0.93:1. Use the table in Section II to match the dimensions of your installation site. Fixed-focus lenses offer no adjustment margin, and even a zoom lens should leave 10–20 cm at both ends.
• Verify the mount and locking mechanism. Genuine lenses are calibrated to the mount of the applicable projector series. You must hear the lens lock into place after installation. A skewed image and soft edges are usually caused by incomplete locking, not by the lens itself.

If you are unsure, take a photo of each nameplate—the projector and the current lens—and send them to us for verification against the actual products.