Optoma BX-CTA23 Extra Long Zoom Lens Fits 9 Models: WU1500, ZK1000, ZK1050, ZK1120

Optoma Original Lens BX-CTA23 Extra Long Zoom is an OEM optical accessory for Optoma engineering projectors. It is a Long Throw lens with a throw ratio of 4.00-7.20:1. The OEM compatibility list covers 9 models. Before installation, simply verify the projector model and panel size; there is no need to use adapter rings to make it fit. The value of an OEM lens lies not in the additional figures in the specification sheet, but in the fact that it is calibrated at the factory to the optical path and mount of that projector series. Once installed, image-circle coverage, edge illumination, and focus travel are all at 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 OEM specifications. For mechanical dimensions, flange distance, and mount type not shown in the specifications table, please verify the details with us using the projector model. Ordering solely because the model numbers are similar risks a lens that will not fit.

2. Converting Throw Ratio into Installation Distance

The throw ratio is the ratio of installation distance to image width. This OEM lens is a zoom lens (4.00-7.20:1). A given image size corresponds to a range of distances, and the lens can focus anywhere within that range during installation.

These figures represent the clear distance from the front element of the lens to the screen and do not include space for rear ventilation or cable connections. They are calculated for a 16:10 image; actual distances should be confirmed by on-site measurement and the OEM manual.

Image quality varies at the two ends of the zoom range: near the short end, the image is brighter and the edges are slightly softer; near the long end, the edges are sharper and brightness decreases slightly. Where 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 (9 Models)

The table below is taken from the OEM model compatibility list. Brightness and resolution are populated from the model database; entries that cannot be obtained are marked "—", with no assumptions made.

For models not on the list, please send us photos of the projector nameplate and the existing lens so we can verify compatibility. Platforms of the same generation often share the same mount, but ordering based on a similar model number is not worth the risk.

Throw Ratios by Model Series

The rated throw ratio varies when the same BX-CTA23 Extra Long Zoom is installed on the series below, so select the value based on the actual projector series.

4. Three Checks Before Replacement

• Confirm the projector imaging chip and resolution. OEM lenses are designed for a specific panel size. If the panel specifications differ, the image circle cannot cover the full image, resulting in dark corners or edge light loss.
• Calculate the installation distance first. This lens has a rated throw ratio of 4.00-7.20:1. Use the table in Section 2 to calculate the distance for your venue. Prime lenses provide no adjustment margin, and zoom lenses should also allow an additional 10–20 cm at both ends.
• Verify the mount and locking mechanism. OEM lenses are calibrated to the mount of the corresponding projector series. You must hear the lens click into the locked position after installation. A skewed image or soft edges are usually caused by incomplete locking, not by a defect in the lens.

If you are unsure, take one photo of each the projector nameplate and the lens nameplate and send them to us. Verification against the actual hardware is the most reliable approach.