Optoma BX-CTA27 Long Zoom Lens for ZU1700 ZU1900 ZU2200

Optoma Original Lens BX-CTA27 Long Zoom is a genuine factory-supplied optical accessory for Optoma professional projectors. It is a long-throw lens (Long Throw) with a throw ratio of 7.20-10.80:1. The official compatibility list covers 3 projector models. Before installation, simply verify the projector model and panel size; there is no need to use an adapter ring as a workaround. The value of an original lens lies not in the extra rows of figures in the specification sheet, but in the fact that its optical path and mount are calibrated at the factory for the corresponding projector series. Once installed, the image circle, edge illumination, and focusing travel are all at their design values, so keystone correction is not needed to compensate for image quality.

I. Lens Specifications

Factory specifications take precedence. For mechanical dimensions, flange distance, and mount type not shown in the specification table, please contact us with the projector model for verification. Ordering solely on the basis of a similar model carries the risk that the lens will not fit.

II. Calculating Installation Distance from Throw Ratio

A throw ratio is the ratio of the installation distance to the image width. This genuine factory lens is a zoom lens (7.20-10.80:1), so a given image size corresponds to a range of installation distances; when installed, the lens can focus anywhere within that range.

The values above are clear distances from the front face of the lens to the screen and do not include clearance for cooling and cable connections at the rear of the projector. They are calculated for a 16:10 image; actual distances must be verified through on-site measurement and the manufacturer's manual.

Image quality differs at the two ends of the zoom range: near the close end, the image is brighter and the edges are slightly softer; near the far end, the edges are sharper and brightness is slightly lower. Where the venue allows, it is recommended to use a position around the middle of the range. After installation, first find the sharpest image using the focus ring, and then fine-tune the shift.

III. Compatible Models (3 Models)

The following table is taken from the official compatibility list. Brightness and resolution are populated from the model database; where data is unavailable, “—” is shown, with no assumptions made.

For compatibility with models not listed, please send us photos of the projector nameplate and the existing lens for verification. Platforms of the same generation often share the same mount, but ordering based solely on a similar model is not worth the risk.

Throw Ratios by Projector Model Series

The nominal throw ratio differs when the same BX-CTA27 Long Zoom is installed on the following model series, so select the value that corresponds to the projector series actually in use.

IV. Three Checks Before Replacement

• Confirm the projector panel and resolution. The original lens is designed for a specific panel size. If the panel specification differs, the image circle cannot cover the full image, causing vignetting or edge illumination loss after installation.
• Calculate the installation distance first. This lens has a rated throw ratio of 7.20-10.80:1, so apply the table in Section II to your venue's dimensions. A fixed-focus lens offers no adjustment margin, and a zoom lens also needs a 10–20 cm allowance at both ends.
• Verify the mount and locking mechanism. The original lens is calibrated to the mount used on that projector series, and you must hear it lock into place after installation. 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 existing lens nameplate, and send them to us. Verification against the actual items is the safest approach.