Optoma ZH451 vs Optoma ZK521ST

Optoma ZK521ST is brighter.

	Optoma ZH451	Optoma ZK521STMSRP $2,699

Key differences
White light outputISO
White light outputISO	4,600 lm ISO	5,000 lm ISO
Native resolution
Native resolution	1080p (1920 × 1080)	—
Throw ratio
Throw ratio	1.4–2.24:1	0.79:1
Fan noise
Fan noise	Max 31 dB(A) · Eco 29 dB(A)	Max 29 dB(A) · Eco 29 dB(A)
MSRP
MSRP	—	$2,699
Room fit80″100″120″150″
Distance to screen
Distance to screen	3.1–5.0 m	1.7 m
Picture
White light outputISO
White light outputISO	4,600 lm ISO	5,000 lm ISO
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
Addressable resolution
Addressable resolution	—	4K UHD (3840 × 2160)
Dynamic contrast
Dynamic contrast	3,000,000:1	2,000,000:1
Colour bit depth (per channel)
Colour bit depth (per channel)	10 bit	—
3D
3D	Yes	Yes
3D formats
3D formats	Frame packing, Side-by-side, Top-bottom	Frame packing, Side-by-side, Top-bottom
3D glasses sync
3D glasses sync	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	—
Optics
Throw ratio
Throw ratio	1.4–2.24:1	0.79:1
Image size
Image size	30–300 in	30–300 in
Projection offset
Projection offset	116%	104%
Zoom
Zoom	Optical	None
Zoom ratio
Zoom ratio	1.6×Derived	—
Focal length
Focal length	20.91–32.62 mm	11.6 mm
Aperture (f-number)
Aperture (f-number)	2.5–3.26	—
Focus
Focus	Manual	Manual
Autofocus
Autofocus	No	—
Vertical lens shift
Vertical lens shift	—	0–21%
Vertical keystone
Vertical keystone	30°	15°
Horizontal keystone
Horizontal keystone	30°	15°
Corner correction
Corner correction	4-corner	4-corner
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 16.7 ms · 120 Hz 8.6 ms · 4K UHD: 60 Hz 16.7 ms
Inputs & control
HDMI inputs
HDMI inputs	2 × HDMI 2.0	2 × HDMI 2.0
Other video inputs
Other video inputs	VGA	VGA
Max input resolution
Max input resolution	4K UHD	—
Audio inputs
Audio inputs	3.5 mm	3.5 mm
Control ports
Control ports	RS-232, 12 V trigger	RS-232, 12 V trigger
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	—
Audio outputs
Audio outputs	3.5 mm	3.5 mm
HDMI audio return
HDMI audio return	NoneDerived	NoneDerived
Physical & installation
Dimensions (W × D × H)
Dimensions (W × D × H)	274 × 216 × 114 mm	274 × 216 × 114 mm
Weight
Weight	2,998 g	3,000 g
Colours
Colours	—	White
Orientations
Orientations	Table, Ceiling, Rear, Portrait, 360°	Portrait, 360°
Ceiling mount
Ceiling mount	M4, screws ≥ 10 mm	—
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	—
Altitude
Altitude	2,500 m · high-altitude mode	3,048 m
Power draw
Power draw	Max 170 W · Eco 120 W	Max 196 W · Eco 147 W
Standby
Standby	Up to 0.5 W	Up to 0.5 W
Power supply
Power supply	External adapter	—
Mains input
Mains input	100–240 V · 50/60 Hz	100–240 V · 50/60 Hz
Fan noise
Fan noise	Max 31 dB(A) · Eco 29 dB(A)	Max 29 dB(A) · Eco 29 dB(A)
Safety & support
Laser class
Laser class	Class 1	Class 1
Risk group
Risk group	RG2	RG2
Hazard distance
Hazard distance	—	1 m
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	https://region-resource.optoma.com/products/documents/wFtzMmyO3OCool38MbOjdfDaDBHsVvtzzQkcczrK.pdf
In the box
In the box
In the box	Power cord, Remote, Remote batteries, User manual	Power cord, Remote, Remote batteries, User manual