NEC NP51ZL Short Zoom Lens: Compatible with PA1505UL-B PA1505UL-W PA1705UL-B PA1705UL-W

NEC Original Lens NP51ZL Short Zoom is an OEM optical accessory for NEC professional projectors. It is a short-throw (Short Throw) lens with a throw ratio of 0.53-0.65:1. The OEM compatibility list covers 4 projector models. Before installation, simply verify the projector model and panel size; no adapter ring workaround is needed. The value of an OEM lens lies not in extra rows of specifications, but in the fact that it is factory-calibrated to the optical path and lens mount of the corresponding projector series: once installed, the image circle, edge illumination, and focusing travel all operate as designed, with no need to use keystone correction to compensate for image quality.

1. Lens Specifications

Brand	NEC (NEC)
Lens Model	NP51ZL Short Zoom
Throw Ratio	0.53-0.65:1
Product Type	Short Throw (Short Throw)
Compatible Models	4 projector models
Warranty	12 months; damage not caused by the user is covered through after-sales service, based on the date on the shipping invoice

These specifications are subject to the original manufacturer’s specifications. For mechanical dimensions, flange distance, and lens-mount type not shown in the specification table, please contact us with the projector model for verification. Ordering solely based on a similar model carries the risk that the lens will not fit.

2. Converting Throw Ratio into Installation Distance

The throw ratio is the ratio of the installation distance to the image width. This OEM lens is a zoom lens (0.53-0.65:1), so a given image size corresponds to a range of installation distances. The lens can focus at any distance within that range.

Image Size	Image Width	Required Installation Distance
100 inches	2.15 m	approx. 1.14 – 1.40 m
120 inches	2.58 m	approx. 1.37 – 1.68 m
150 inches	3.22 m	approx. 1.71 – 2.10 m
200 inches	4.30 m	approx. 2.28 – 2.79 m

These distances represent the clear distance from the front surface of the lens to the projection screen and do not include space behind the projector for ventilation and cable connections. They are calculated on the basis of a 16:10 image; actual installation should follow on-site measurements and the original manufacturer’s manual.

Image quality varies at the two ends of the zoom range: at the shorter-distance end, the image is brighter but the edges appear slightly softer; at the longer-distance end, the edges are sharper but brightness decreases slightly. Where venue conditions allow, use a distance near the middle of the range. After installation, first find the sharpest setting on the focus ring, then fine-tune the lens shift.

3. Compatible Projector Models (4 Models)

The following table is taken from the OEM compatibility list. Brightness and resolution are filled in from the model database; unavailable values are shown as “—” rather than estimated.

Model	Brightness	Resolution
PA1505UL-B	14000 lumens	1920x1200
PA1505UL-W	14000 lumens	1920x1200
PA1705UL-B	16000 lumens	1920x1200
PA1705UL-W	16000 lumens	1920x1200

To check whether a model outside the list is compatible, please send us photos of the projector nameplate and existing lens for verification—platforms of the same generation often share a lens mount, but placing an order based only on a similar model is not worth the risk.

Throw Ratios by Projector Series

The rated throw ratio of the same NP51ZL Short Zoom varies by projector series. Use the value for the series of the projector you actually own when selecting a lens.

Model Series	Throw Ratio
—	0.53-0.65:1

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 vignetting or edge light loss after installation.
• Calculate the installation distance first.This lens has a rated throw ratio of 0.53-0.65:1. Use the table in Section 2 to match your venue’s screen size; a fixed-focus lens offers no adjustment margin, while even a zoom lens should allow an additional 10–20 cm at both ends of the range.
• Verify the lens mount and locking mechanism.The OEM lens is calibrated to the lens mount of the corresponding projector series, and you must hear it click into the locked position after installation. Most skewed images and soft edges result from the lens not being fully locked, rather than a defect in the lens itself.

If you are unsure, send us one photo each of the projector nameplate and the nameplate on the existing lens. Verification against the actual hardware is the safest approach.