Optoma BX-CTA15 Short Zoom Standard Throw Lens: Compatible with WU630 ZU1050 ZU1100 ZU1300 ZU650

Optoma Original Lens BX-CTA15 Short Zoom is a genuine optical accessory for Optoma installation projectors. It belongs to the standard throw category, with a throw ratio of 0.75-0.95:1, and is designed for 0.67" DLP (ProScene ZU series) panels. The original compatibility list covers 10 projector models; before installation, simply verify the projector model and panel size — no adapter rings are needed. The value of an original lens is not about extra rows of numbers in a spec sheet, but about being calibrated at the factory to the optical path and bayonet of that series: once mounted, the image circle, edge illumination, and focus travel all match design values, so you don't need keystone correction to compensate for image quality.

1. Lens Specifications

Brand	Optoma
Lens Model	BX-CTA15 Short Zoom
Throw Ratio	0.75-0.95:1
Product Type	Standard Throw
Compatible Panel	0.67" DLP (ProScene ZU series)
Covered Models	10
Warranty	12 months; non-human damage is eligible for after-sales service, based on the date on the shipping document

The above specifications are subject to the original manufacturer's specifications. For mechanical dimensions, flange focal distance, and bayonet type that are not shown in the spec table, please verify with us based on your projector model — ordering based on similar model numbers carries the risk of incompatibility.

2. Converting Throw Ratio to Installation Distance

Throw ratio is the ratio of installation distance to image width. This original lens is a zoom lens (0.75-0.95:1), so the same image size corresponds to a range of distances; as long as installation falls within this range, focus can be achieved.

Image Size	Image Width	Required Installation Distance
100 inches	2.15 m	Approx. 1.61 – 2.04 m
120 inches	2.58 m	Approx. 1.93 – 2.45 m
150 inches	3.22 m	Approx. 2.42 – 3.06 m
200 inches	4.30 m	Approx. 3.22 – 4.08 m

The above figures are the clear distance from the lens face to the screen, excluding rear ventilation and cabling space behind the projector body. Calculated for 16:10 aspect ratio; actual values are subject to on-site measurement and the original manufacturer's manual.

Image quality differs at the two ends of the zoom range: toward the near end, the image is brighter with slightly softer edges; toward the far end, edges are sharper with slightly reduced brightness. Where space permits, it is recommended to land in the middle of the range. After installation, first find the sharpest position on the focus ring, then fine-tune the shift.

3. Compatible Models (10)

The table below is taken from the original manufacturer's compatibility list; brightness and resolution are filled in from the model database, with "—" where unavailable, without speculation.

Model	Brightness	Resolution
WU630	6000 lumens	1920x1200
ZU1050	10000 lumens	WUXGA,1920 x 1200
ZU1100	11000 lumens	WUXGA,1920 x 1200
ZU1300	13000 lumens	WUXGA,1920 x 1200
ZU650	5500 lumens	1920x1200
ZU650+	5500 lumens	1920x1200
ZU660	6000 lumens	1920x1200
ZU750	7500 lumens	WUXGA,1920 x 1200
ZU850	8500 lumens	WUXGA,1920 x 1200
ZU860	8500 lumens	WUXGA,1920 x 1200

For models outside this list, please send us a photo of the projector nameplate and the existing lens for verification — same-generation platforms often share the same bayonet, but ordering based on similar model numbers is a risk not worth taking.

Throw Ratios Across Different Model Series

The same BX-CTA15 Short Zoom mounted on the following series has different nominal throw ratios; selection should be based on the actual series of your projector.

Model Series	Throw Ratio
—	0.75-0.95:1

4. Three Things to Confirm Before Replacement

• Panel size must match. The BX-CTA15 Short Zoom is designed for 0.67" DLP (ProScene ZU series) panels. For projectors with a different panel size or resolution, even if the bayonet fits, the image circle and edge illumination will be problematic.
• Calculate the installation distance first. This lens has a nominal throw ratio of 0.75-0.95:1; use the table in Section 2 to match your venue dimensions. Prime lenses have no margin, and even for zoom lenses, allow 10–20 cm at both ends.
• Check the bayonet and locking. The original lens is calibrated to the bayonet of that series; after mounting, you must hear it lock into place. Skewed images or soft edges are usually caused by incomplete locking, not by the lens itself.

If unsure, take a photo of the projector nameplate and the existing lens nameplate and send them to us — verification against the actual hardware is the most reliable approach.