Optoma BX-CTA03 Zoom Long-Throw Lens for ZU1100 ZU1300 ZU1050 ZU850 ZU660

Optoma Original Lens BX-CTA03 Zoom is the factory-supplied optical accessory for Optoma engineering projectors. It is a Long Throw lens with a throw ratio of 1.52-2.92:1 for a 0.67" DLP (ProScene ZU series) panel. The official compatibility list covers 5 models; before installation, simply verify the projector model and panel size—there is no need to make do with an adapter ring. The value of a genuine lens lies not in the extra figures in its specifications, but in the fact that it is calibrated at the factory to the optical path and mount of the corresponding projector series. Once installed, the image circle, edge illumination, and focusing range all meet the 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 official manufacturer specifications. For mechanical dimensions, flange distance, and mount type not shown in the specification table, please send us the projector model for verification. Placing an order based solely on a similar model carries the risk that the lens will not fit.

2. Calculating Installation Distance from Throw Ratio

The throw ratio is the ratio of installation distance to image width. This genuine lens is a zoom lens (1.52-2.92:1), so a given image size corresponds to a range of installation distances. It can focus at any distance within that range.

These figures represent the clear distance from the front of the lens to the projection screen and do not include space behind the projector for cooling and cable connections. They are calculated for a 16:10 image; actual distances should be verified on site and according to the manufacturer's manual.

Image quality differs at the two ends of the zoom range: near the short-throw end, the image is brighter and the edges are slightly softer; near the long-throw end, the edges are sharper and the image slightly dimmer. When the venue allows, use the middle of the range. After installation, first find the sharpest position on the focus ring, then fine-tune the lens shift.

3. Compatible Models (5 Models)

The following table is taken from the manufacturer's compatibility list. Brightness and resolution are populated from the model database; where the data is unavailable, an em dash (—) is shown rather than making assumptions.

To check whether a model outside the list is supported, send us photos of the projector nameplate and the existing lens. Platforms from the same generation often share a mount, but ordering based on a similar model carries unnecessary risk.

Throw Ratios by Projector Series

The specified throw ratio varies by series when the same BX-CTA03 Zoom is used. Select the value based on the series of the actual projector.

4. Three Checks Before Replacement

• Make sure the panel size matches. BX-CTA03 Zoom is designed for a 0.67" DLP (ProScene ZU series) panel. On a projector with a different panel size or resolution, the image circle and edge illumination may be affected even if the lens fits the mount.
• Calculate the installation distance first. This lens has a rated throw ratio of 1.52-2.92:1. Use the table in Section 2 to calculate the distance for your venue; a fixed-focus lens offers no adjustment margin, and a zoom lens should also allow an extra 10–20 cm at both ends.
• Verify the mount and locking mechanism. The genuine lens is calibrated to the mount of projectors in this series. After installation, make sure you hear the lens click into the locked position. A skewed image 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 of the current lens nameplate and send them to us. Verification against the actual hardware is the most reliable approach.