Eiki AH-AC23030 Zoom Long Throw Projector Lens: Compatible with EK-831DU EK-831U EK-833DU EK-836DU

Eiki Original Lens AH-AC23030 Zoom is a genuine optical accessory for Eiki installation projectors, belonging to the long throw category, with a throw ratio of 5.52-8.83:1. The original compatibility list covers 4 projector models; before installation, simply verify against the projector model and panel size — no adapter rings needed. The value of an original lens isn't a few extra rows of numbers in the spec sheet, but that it is calibrated at the factory to the optical path and bayonet of that series of projector bodies: once mounted, the image circle, edge illumination, and focus travel are all at their design values, so you don't need keystone correction to compensate for image quality.

1. Lens Specifications

Brand	Eiki
Lens Model	AH-AC23030 Zoom
Throw Ratio	5.52-8.83:1
Product Type	Long Throw
Compatible Models	4
Warranty	12 months; after-sales service available for non-human damage, 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 not shown in the spec table, please verify with us against your projector model; ordering based on model similarity alone 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 (5.52-8.83:1), 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. 11.87 – 18.98 m
120 inches	2.58 m	Approx. 14.24 – 22.78 m
150 inches	3.22 m	Approx. 17.80 – 28.48 m
200 inches	4.30 m	Approx. 23.74 – 37.97 m

The above are net distances from the lens front to the screen, excluding rear ventilation and cabling space. Calculated at 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 the edges are sharper with slightly reduced brightness. Where the venue allows, 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 (4)

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

Model	Brightness	Resolution
EIKI EK-831DU	—	—
EIKI EK-831U	—	—
EIKI EK-833DU	—	—
EIKI EK-836DU	—	—

To check whether models outside the list are usable, please send us photos of the projector nameplate and the existing lens for verification — same-generation platforms often share bayonets, but the risk of ordering based on model similarity isn't worth it.

Throw Ratios Across Model Series

The same AH-AC23030 Zoom mounted on the following series has different nominal throw ratios; selection should be based on the actual series of the projector body.

Model Series	Throw Ratio
—	5.52-8.83:1

4. Three Things to Confirm Before Replacement

• Confirm the projector's chip and resolution. Original lenses are designed for specific panel sizes; with a different panel specification, the image circle cannot cover it, resulting in vignetting or edge light loss after installation.
• Calculate the installation distance first. This lens has a nominal throw ratio of 5.52-8.83:1; apply it to your venue dimensions using the table in Section 2. Prime lenses have no margin, and even zoom lenses should leave 10–20 cm at both ends.
• Verify the bayonet and locking. Original lenses are calibrated to that series' projector bayonet; after installation you must hear it lock into place. Image skew and soft edges are mostly due to incomplete locking, not 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.