NEC NP21ZL-4K Zoom Long Throw Projector Lens: PX1005QL-B PX1005QL-B-18 PX1005QL-W PX1005QL-W-18

NEC Original Lens NP21ZL-4K Zoom is a genuine optical accessory for NEC engineering projectors, belonging to the long throw category, with a throw ratio of 5.25-8.28:1. 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 on a spec sheet, but that it is calibrated at the factory to the optical path and mount of that series: once installed, the image circle, edge illumination, and focus travel are all at their design values, with no need to compensate for image quality using keystone correction.

1. Lens Specifications

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

2. Converting Throw Ratio to Installation Distance

The throw ratio is the ratio of installation distance to image width. This original lens is a zoom lens (5.25-8.28:1), so the same image size corresponds to a range of distances; as long as installation falls within this range, focus can be achieved.

The above are clear distances from the lens front 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 the 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 (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.

To determine 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 mounts, but the risk of ordering based on a similar model number isn't worth it.

Throw Ratios Across Model Series

The same NP21ZL-4K Zoom installed on the following series does not have the same nominal throw ratio; selection must use the value for the actual projector series.

4. Three Things to Confirm Before Replacement

• Confirm the projector's chip and resolution. The original lens is designed for a specific panel size; 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 5.25-8.28:1; use the table in Section 2 to map it to your venue's dimensions. Prime lenses have no margin, and even zoom lenses should leave 10–20 cm at both ends.
• Verify the mount and locking. The original lens is calibrated to the mount of that projector series; after installation, you must hear it lock into place. Image skew and soft edges are mostly due to incomplete locking, not a problem with 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 safest approach.