Digital Projection SL-121 Ultra Short Throw Lens Guide

Genuine Digital Projection SL-121 Lens is an OEM optical accessory for Digital Projection professional projectors. It is an ultra-short-throw (Ultra Short Throw) lens with a throw ratio of 0.37:1 (Fixed Focus, UST), designed for the 0.95inch 3DLP(HIGHlite) inch panel. The official compatibility list covers 2 models; before installation, simply verify the projector model and panel size, with no need to force compatibility using adapter rings. The value of an OEM lens lies not in the additional figures in the specifications table, but in its factory calibration to the optical path and mount of the relevant projector series. Once installed, the image circle, edge illumination, and focus travel meet the design specifications, eliminating the need to compensate for image quality with keystone correction.

1. Lens Specifications

These specifications are subject to the OEM specifications. For mechanical dimensions, flange distance, and mount type not shown in the specifications table, please contact us with the projector model. Placing an order solely because the model names are similar risks a fit failure.

2. Calculating Installation Distance from Throw Ratio

The throw ratio is the ratio of installation distance to image width. This OEM lens has a fixed-focus design (0.37:1 (Fixed Focus, UST)), so installation distance varies linearly with image size, with no adjustment range. Accurate measurements are essential before installation.

These figures represent the clear distance from the lens front surface to the screen and do not account for ventilation and cabling space behind the chassis. They are calculated for a 16:10 image; in practice, rely on on-site measurements and the OEM manual.

3. Compatible Models (2 Models)

The following table is taken from the OEM compatibility list. Brightness and resolution are populated from the model database; where the data is unavailable, “—” is shown rather than estimated.

To verify whether a model not listed here is compatible, send us photos of the projector nameplate and the existing lens. Projector platforms of the same generation often share mounts, but ordering based only on a similar model name carries unnecessary risk.

Throw Ratios by Model Series

When the same SL-121 lens is installed on the series listed below, the nominal throw ratio may differ. Use the value corresponding to the actual projector series when selecting.

4. Three Checks Before Replacement

• Confirm that the panel size matches.SL-121 is designed for the 0.95inch 3DLP(HIGHlite) inch panel. Even if the mount fits a projector with a different panel size or resolution, its image circle and edge illumination will be compromised.
• Calculate the installation distance first.This lens has a rated throw ratio of 0.37:1 (Fixed Focus, UST); use the table in Section 2 with the dimensions of your installation site. A fixed-focus lens offers no adjustment range, and even a zoom lens requires 10–20 cm of clearance at both ends.
• Verify the mount and locking mechanism.The OEM lens is calibrated to the mount of the relevant projector series, and you must hear the lock engage fully after installation. A skewed image or soft edges are usually caused by incomplete locking rather than an issue with the lens itself.

If you are unsure, send us one photo each of the projector nameplate and the existing lens nameplate. Verification against the actual hardware is the safest approach.