Optoma BX-CTA13 Ultra Long Zoom Long Throw Lens Guide: Fits 12 Models incl. WU630 ZU1050 ZU1100

Optoma Genuine Lens BX-CTA13 Ultra Long Zoom is a factory-supplied optical accessory for Optoma professional projectors. It is a long-throw (Long Throw) lens with a throw ratio of 2.90-5.50:1, designed for 0.67" DLP (ProScene ZU series) inch panels. The official compatibility list covers 12 models; before installation, simply verify the projector model and panel size—there is no need to make do with adapter rings. The value of a genuine lens lies not in the extra figures in the specification sheet, but in the fact that it is calibrated at the factory to the optical path and mount of that series. Once installed, the image circle, edge illumination, and focusing travel are all at their design values, so there is no need to compensate for image quality with keystone correction.

1. Lens Specifications

The above specifications are subject to the manufacturer's official specifications. For mechanical dimensions, flange distance, and mount type not shown in the specifications table, please provide your projector model so we can verify it. Placing an order based solely on a similar model carries the risk that the lens will not fit.

2. Calculating Installation Distance from the Throw Ratio

The throw ratio is the ratio of the installation distance to the image width. This genuine lens is a zoom lens (2.90-5.50:1), so a given image size corresponds to a range of installation distances. Any position within this range can achieve proper focus during installation.

The distances above are clear distances from the front of the lens to the screen and do not account for space behind the projector for heat dissipation and cable connections. They are calculated for a 16:10 image format; actual distances should be confirmed through on-site measurements and the manufacturer's manual.

Image quality differs at the two ends of the zoom range: the image is brighter with slightly softer edges toward the near end, while the edges are sharper and brightness is slightly lower toward the far end. When the venue allows, use the middle of the range. After installation, first find the sharpest position using the focus ring, then fine-tune the lens shift.

3. Compatible Models (12 Units)

The following table is based on the manufacturer's official compatibility list. Brightness and resolution have been populated from the model database; values that could not be obtained are marked '—' and have not been estimated.

To determine whether a model outside the list is compatible, send us photos of the projector nameplate and the existing lens for verification. Platforms of the same generation often share the same mount, but the risk of ordering based on a similar model is not worth taking.

Throw Ratios by Model Series

When the same BX-CTA13 Ultra Long Zoom is used with the series listed below, the rated throw ratio varies. Use the value for the actual projector series when selecting a lens.

4. Three Checks Before Replacement

• The panel size must match. BX-CTA13 Ultra Long Zoom is designed for 0.67" DLP (ProScene ZU series) inch panels. Even if the mount fits, projectors with a different panel size or resolution may experience problems with the image circle and edge illumination.
• Calculate the installation distance first. This lens has a rated throw ratio of 2.90-5.50:1. Use the table in Section 2 with your venue dimensions. Fixed-focus lenses provide no adjustment margin, and even a zoom lens should allow an additional 10–20 cm at both ends.
• Verify the mount and locking mechanism. The genuine lens is calibrated to the mount of that projector series. After installation, you must hear the lens lock fully into place. Image skew and soft edges are usually caused by incomplete locking rather than a problem with the lens itself.

If you are unsure, take one photo of the projector nameplate and one photo of the existing lens nameplate and send them to us. Physical verification is the safest approach.