BenQ LS2LT1 Semi Long Zoom Standard Throw Lens Review: LU9235 PX9230 Fit

BenQ Original Lens LS2LT1 Semi Long Zoom is an original optical accessory for BenQ engineering projectors, belonging to the standard throw category (Standard Throw), with a throw ratio of 1.93:1 - 2.90:1. The original compatibility list covers 2 models — simply verify against the projector model and panel size before installation, no adapter rings needed. The value of an original lens lies not in the extra rows of numbers on a spec sheet, but in the fact that it is calibrated at the factory to the optical path and lens mount of that series: once mounted, the image circle, edge illumination and focusing travel are all at their designed values, so there is no need to patch up image quality with keystone correction.

I. Lens Specifications

The above specifications are subject to the original manufacturer's specs. Mechanical dimensions, flange distance and mount type are not listed in the table above — please check these with us against your projector model, as ordering on the basis of a similar model number carries the risk of a lens that simply 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 original lens is a zoom lens (1.93:1 - 2.90:1), so a single image size corresponds to a range of distances, and focus can be achieved anywhere within that range during installation.

The above is the clear distance from the front element of the lens to the screen, without allowing for heat dissipation and cabling space at the rear of the projector. Figures are calculated on a 16:10 aspect ratio; actual results depend on on-site measurement and the manufacturer's manual.

Image quality differs at the two ends of the zoom range: near the short-throw end the image is brighter but the edges are slightly soft; near the long-throw end the edges are crisper but brightness drops slightly. Where the venue allows, it is recommended to aim for the middle of the range, and after mounting, first find the sharpest position on the focus ring and then fine-tune the lens shift.

III. Compatible Models (2 models)

The table below is taken from the original compatibility list; brightness and resolution are filled in from the model database, and where the data cannot be retrieved it is shown as "—" with no speculation.

For models outside the list, please send us a photo of the projector's nameplate and of your existing lens so we can verify compatibility — platforms of the same generation often share the same lens mount, but the risk of ordering on the basis of a similar model number is not worth taking.

Throw Ratio by Projector Series

The nominal throw ratio differs when the same LS2LT1 Semi Long Zoom is used on the series below, so the actual series of your projector should be used as the basis for selection.

IV. Three Things to Confirm Before Replacement

• Confirm the projector panel and resolution.Original lenses are designed for a specific panel size; when the panel specs differ, the image circle cannot cover the full frame, resulting in vignetting or edge light loss after mounting.
• Calculate the installation distance first.This lens has a nominal throw ratio of 1.93:1 - 2.90:1 — apply it to your venue dimensions using the table in Section II; a fixed-focus lens leaves no margin, and even with a zoom lens you should allow an extra 10–20 cm at both ends.
• Check the mount and locking mechanism.Original lenses are calibrated to the lens mount of that projector series, and after mounting you must hear it lock into place; a skewed image or soft edges are usually caused by the lens not being fully locked, not by a fault in the lens itself.

If you are unsure, take one photo each of the projector's nameplate and the nameplate of your existing lens and send them to us — verifying against the actual hardware is the most reliable approach.