Optoma BX-DLTZ1 Long Zoom Lens Review: For PRO8000 and TH7500-NL

Optoma genuine lens BX-DLTZ1 Long Zoom is an original optical accessory for Optoma engineering projectors, belonging to the long throw (Long Throw) category, with a throw ratio of 1.93-3.71:1. The official compatibility list covers 2 models; before installation, simply verify the body model and panel size — no need to make do with adapter rings. The value of an original factory lens lies not in a few extra rows of figures on the spec sheet, but in the fact that it is calibrated from the factory to the optical path and mount of that model series: once mounted, image circle, edge illumination, and focus travel are all design values, so there is no need to use keystone correction to patch up the picture quality.

I. Lens Specifications

The above specifications are subject to the original factory specifications. For mechanical dimensions, flange distance, and mount type that are not shown in the spec table, please check with us using the projector body model; ordering directly based on a similar-looking model carries the risk that the lens simply will not fit.

II. Converting Throw Ratio into Installation Distance

The throw ratio is the ratio of the installation distance to the image width. This genuine factory lens is a zoom lens (1.93-3.71:1), so a single image size corresponds to a range of distances, and any position within that range can be brought into focus during installation.

The above is the clear distance from the front element of the lens to the screen, excluding space for rear heat dissipation and cable connections. Figures are calculated on a 16:10 aspect ratio; in practice, on-site measurement and the original factory manual take precedence.

Image quality differs at the two ends of the zoom range: near the short end the image is brighter and the edges slightly softer; near the long end the edges are sharper and brightness drops slightly. Where the venue allows, we recommend positioning in the middle of the range; after mounting, first find the sharpest point on the focus ring, then fine-tune the lens shift.

III. Compatible Models (2 units)

The table below is taken from the original factory compatibility list; brightness and resolution are back-filled from the model database, and are shown as「—」where they cannot be retrieved, with no speculation.

For models outside this list, please send us photos of the body nameplate and the existing lens for verification — platforms of the same generation often share the same mount, but the risk of ordering on the basis of a similar model name is not worth taking.

Throw Ratios by Model Series

The nominal throw ratio varies depending on the series to which the same BX-DLTZ1 Long Zoom is fitted, so model selection must be based on the actual series of the projector body.

IV. Three Things to Confirm Before Replacement

• Confirm the chip and resolution of the projector body.Original factory lenses are designed for a specific panel size; when the panel specification differs, the image circle cannot cover the full area, resulting in vignetting or edge light loss after mounting.
• Calculate the installation distance first.This lens has a rated throw ratio of 1.93-3.71:1; use the table in Section II to map it onto your own venue dimensions; a fixed-focus lens leaves no margin, and a zoom lens still needs 10–20 cm reserved at both ends.
• Verify the mount and locking mechanism.Original factory lenses are calibrated to the mount of that model series, and you must hear it click into the locked position after mounting; a skewed image or soft edges are usually caused by the lens not being fully locked, rather than by any problem with the lens itself.

If you are unsure, take one photo of the projector body nameplate and one of the nameplate on the existing lens and send them to us — verification against the physical items is the safest approach.