Optoma ZH451 vs Optoma ZK420UST

Optoma ZH451 is lighter. Optoma ZK420UST is better for gaming.

	Optoma ZH451	Optoma ZK420UST

Key differences
White light output
White light output	4,600 lm ISO	4,200 lm ANSI
Native resolution
Native resolution	1080p (1920 × 1080)	—
Throw ratio
Throw ratio	1.4–2.24:1	0.25:1
Lowest input lag
Lowest input lag	8.6 msDerived	4.3 msDerived
HDR formats
HDR formats	—	HDR10, HLG
Fan noise
Fan noise	Max 31 dB(A) · Eco 29 dB(A)	Max 34 dB(A) · Eco 29 dB(A)
Room fit80″100″120″150″
Distance to screen
Distance to screen	3.1–5.0 m	0.55 m
Picture
White light output
White light output	4,600 lm ISO	4,200 lm ANSI
Brightness uniformity
Brightness uniformity	75%	75%
Imaging technology
Imaging technology	DLP	DLP
Native resolution
Native resolution	1080p (1920 × 1080)	—
Native aspect
Native aspect	16:9Derived	16:9Derived
Pixel shift
Pixel shift	—	XPR 4-way
Addressable resolution
Addressable resolution	—	4K UHD (3840 × 2160)
Dynamic contrast
Dynamic contrast	3,000,000:1	500,000:1
Colour bit depth (per channel)
Colour bit depth (per channel)	10 bit	—
Gamma / EOTF presets
Gamma / EOTF presets	—	2.2, 2.4
HDR formats
HDR formats	—	HDR10, HLG
3D
3D	Yes	Yes
3D formats
3D formats	Frame packing, Side-by-side, Top-bottom	Frame packing, Side-by-side, Top-bottom, Frame sequential
3D glasses sync
3D glasses sync	DLP-Link	DLP-Link
Light source
Light source
Light source	Laser (phosphor)	Laser (phosphor)
Light-source life
Light-source life	30,000 h	30,000 h eco
Light output control
Light output control	Steps	Steps
Optics
Throw ratio
Throw ratio	1.4–2.24:1	0.25:1
Image size
Image size	30–300 in	100–150 in
Projection offset
Projection offset	116%	120%
Zoom
Zoom	Optical	None
Zoom ratio
Zoom ratio	1.6×Derived	—
Focal length
Focal length	20.91–32.62 mm	3.7 mm
Aperture (f-number)
Aperture (f-number)	2.5–3.26	2.44
Focus
Focus	Manual	Manual
Autofocus
Autofocus	No	—
Vertical keystone
Vertical keystone	30°	—
Horizontal keystone
Horizontal keystone	30°	—
Corner correction
Corner correction	4-corner	4-corner
Grid warp
Grid warp	—	Yes
Interchangeable lens
Interchangeable lens	—	No
Motion & gaming
Input lag
Input lag	1080p: 60 Hz 17 ms · 120 Hz 8.6 ms · 4K UHD: 60 Hz 16.9 ms	1080p: 60 Hz 17 ms · 120 Hz 8.6 ms · 240 Hz 4.3 ms · 4K UHD: 60 Hz 16.9 ms
Inputs & control
HDMI inputs
HDMI inputs	2 × HDMI 2.0	2 × HDMI 2.0
Other video inputs
Other video inputs	VGA	HDBaseT
Max input resolution
Max input resolution	4K UHD	4K UHD
Audio inputs
Audio inputs	3.5 mm	—
Control ports
Control ports	RS-232, 12 V trigger	RS-232
PJLink
PJLink	Class 2	—
Control-system drivers
Control-system drivers	Crestron, AMX	—
Horizontal scan
Horizontal scan	15–135 kHz	15–150 kHz
Vertical scan
Vertical scan	24–120 Hz	24–240 Hz
Smart platform
Ethernet
Ethernet	Yes	Yes
Audio
Speaker power
Speaker power	15 W	15 W
Speakers
Speakers	1	1
Layout
Layout	Mono	Mono
Audio outputs
Audio outputs	3.5 mm	3.5 mm, HDMI eARC
HDMI audio return
HDMI audio return	NoneDerived	eARCDerived
Physical & installation
Dimensions (W × D × H)
Dimensions (W × D × H)	274 × 216 × 114 mm	327 × 328 × 110 mm
Weight
Weight	2,998 g	4,200 g
Orientations
Orientations	Table, Ceiling, Rear, Portrait, 360°	Portrait, 360°
Ceiling mount
Ceiling mount	M4, screws ≥ 10 mm	M4, 10 mm screws
Ingress protection
Ingress protection	IP6X	IP6X
Environment & power
Operating temperature
Operating temperature	0–40°C	0–40°C
Operating humidity
Operating humidity	0–80%RH	10–85%RH
Altitude
Altitude	2,500 m · high-altitude mode	3,048 m · high-altitude mode
Power draw
Power draw	Max 170 W · Eco 120 W	Max 255 W · Eco 180 W
Standby
Standby	Up to 0.5 W	0.5 W
Power supply
Power supply	External adapter	External adapter
Mains input
Mains input	100–240 V · 50/60 Hz	100–240 V · 50/60 Hz
DC input
DC input	—	24 V
Fan noise
Fan noise	Max 31 dB(A) · Eco 29 dB(A)	Max 34 dB(A) · Eco 29 dB(A)
Safety & support
Laser class
Laser class	Class 1	Class 1
Risk group
Risk group	RG2	RG2
FDA laser notice
FDA laser notice	—	Notice 57
Marks
Marks	FCC	FCC
Warranty
Warranty	—	3 yr (light source 5 yr or 12,000 h)
User manual
User manual	https://region-resource.optoma.com/products/documents/mpTwkm9mUWvfsgMhppFmV04EqeoeeRYWmvKy7tBF.pdf	—
In the box
In the box
In the box	Power cord, Remote, Remote batteries, User manual	Power cord, Power adapter, Remote, Remote batteries, Quick start guide
Remote
Remote	—	IR