The Quick Verdict
Get the Optoma GT2000HDR. It lists at $1,799 MSRP, $900 under the Optoma ZK431ST-B at list, and it mounts at exactly the same distance for exactly the same image width. Optoma also publishes a light-source rating and a warranty term for the GT2000HDR, and it publishes neither for the ZK431ST-B. The ZK431ST-B earns the extra $900 if you want its 3840x2160 resolution over 1920x1080, or if a published input-lag figure matters to you. Check price at The Indoor Golf Shop →
What They Have in Common
The lens is identical: fixed at 0.496:1, with no optical zoom and no lens shift. Both use a laser light source, both are natively 16:9, and both list the same three aspect modes: 4:3, 16:9 and 16:10. The keystone range is the same too, ±15° horizontal and ±15° vertical. Optoma doesn't publish a golf mode for either one.
Where They Differ
Throw and image size: a dead heat
Image width is throw distance divided by throw ratio. These are fixed lenses, so each gives one figure, and it's the same figure for both. From 10 ft back, each throws an image 20.2 ft wide. For a 10 ft wide image, each needs to sit 5.0 ft from the screen. A 0.496 throw ratio is the difference between hanging the projector over the hitting area and hanging it behind you.
With no zoom and no lens shift on either, the mounting distance alone sets the image width. Measure from where the lens will sit to the screen before you commit to a spot. Optoma lists the offset at 116% for the GT2000HDR and 114% for the ZK431ST-B.
Screen shape
Both list 4:3 among their stated modes, so a 4:3 impact screen is covered on paper for either. A square 1:1 shape isn't among the stated modes for either one. That doesn't mean they can't do it. It means Optoma doesn't list it.
Brightness and lag
The GT2000HDR is rated at 3,500 lumens, and Optoma doesn't state the standard behind that figure. The ZK431ST-B is rated at 4,100 lumens to ISO 21118. Those two numbers weren't measured on the same terms, so I'm not calling either one brighter.
Input lag is similar. Optoma lists 16.7 ms at 1080p 60Hz for the ZK431ST-B and publishes no input-lag figure for the GT2000HDR, so there's nothing to compare. If you want a lag number on paper before you buy, only one of these gives you one.
Resolution, rated life, warranty and price
This is where the $900 goes. The ZK431ST-B lists a 3840x2160 resolution against 1920x1080 on the GT2000HDR. Optoma doesn't say how the ZK431ST-B gets to 3840x2160, so I won't call it native or pixel-shift.
The GT2000HDR comes with the paperwork. Its laser is rated for 30,000 hours, and the warranty reads "1 year projector parts and labor; 5 years or 12,000 hours light source." Optoma publishes no light-source life and no warranty term for the ZK431ST-B. The GT2000HDR dates from 2023 and the ZK431ST-B from 2026. The ZK431ST-B is the lighter one by 0.31 lbs (6.3 lbs vs 6.61 lbs), and the dimensions are 10.8 x 4.3 x 8.5 in against 10.79 x 4.49 x 8.50 in.
Who Should Buy Which
Get the Optoma GT2000HDR if:
- You want the same 5.0 ft mount for a 10 ft wide image at $1,799 list instead of $2,699.
- You want a published warranty and a rated light-source life on a projector that's going up on a ceiling mount.
- Your screen is 4:3. It's a stated mode, the same as on the pricier one.
- A 1920x1080 image is what you're after, and you'd rather keep the $900.
Get the Optoma ZK431ST-B if:
- You want 3840x2160 resolution on the impact screen and you're fine with $2,699 at list.
- You want a published input-lag figure: 16.7 ms at 1080p 60Hz.
- You're comfortable without a published warranty term or light-source rating for this model.
- Every bit of weight matters on your mount. It's 6.3 lbs.
If your screen is square, neither one lists 1:1, so that question goes to Optoma rather than to this page.
The Bottom Line
Same lens, same mounting math, same keystone, same stated modes, and no golf mode published for either. The $900 at list buys the ZK431ST-B's 3840x2160 resolution and a published lag figure. The GT2000HDR keeps the money and comes with the rated laser life and warranty terms the ZK431ST-B doesn't publish. If I had to bet on what decides a bay, it's where the projector hangs and how wide the image comes out, and on that these two are identical.