Optoma BX-CTA17 Short Zoom Lens: Compatible with ZU1050 ZU1100 ZU1300 ZU660 ZU750 ZU850 ZU860

Optoma Genuine Lens BX-CTA17 Short Zoom is an original optical accessory for Optoma professional projectors. It is a short-throw lens (Short Throw) with a throw ratio of 0.65-0.75:1, designed for the 0.67" DLP (ProScene ZU series) inch panel. The official compatibility list covers 7 models; simply verify the projector model and panel size before installation, with no need to improvise 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 projectors in that series. Once installed, the image circle, edge illumination, and focusing travel all meet their design values, so there is no need to use keystone correction to compensate for image quality.

1. Lens Specifications

The above specifications are subject to the original manufacturer's specifications. For mechanical dimensions, flange distance, and mount type not listed in the specification table, please contact us with the projector model so that we can verify the details. 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 the installation distance to the image width. This genuine lens is a zoom lens (0.65-0.75:1), so each image size corresponds to a range of distances, and the lens can focus at any point within that range during installation.

The distances above are clear measurements from the front surface of the lens to the screen and do not allow for ventilation and cable connection space at the rear of the projector. They are calculated for a 16:10 image; actual distances are subject to on-site measurement and the manufacturer's manual.

Image quality differs at the two ends of the zoom range: toward the short end, the image is brighter and the edges are slightly softer; toward the long end, the edges are sharper and brightness decreases slightly. When venue conditions allow, use the middle of the range. After installation, set the focus ring to the sharpest position, then fine-tune the lens shift.

3. Compatible Models (7 Models)

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

For models not on the list, please send us photos of the projector nameplate and the current lens for verification. Platforms from the same generation often share a mount, but the risk of ordering based on a similar model is not worth taking.

Throw Ratios by Model Series

The specified throw ratio of the same BX-CTA17 Short Zoom varies across the series listed below. When selecting a lens, use the value for the series of the actual projector.

4. Three Checks Before Replacement

• Confirm that the panel size matches. BX-CTA17 Short Zoom is designed for the 0.67" DLP (ProScene ZU series) inch 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 0.65-0.75:1. Use the table in Section 2 to apply this ratio to your venue's dimensions. A fixed-focus lens offers no adjustment margin, and even a zoom lens needs 10–20 cm of clearance at both ends.
• Check the mount and locking mechanism. The genuine lens is calibrated to the projector mount for that series. After installation, you must hear the lens click into the fully locked position. A skewed image or soft edges are usually due to 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 safest approach.