In depth comparison and review of ASUS ZenFone Zoom (ZX551ML) and Realme C21. Compare sizes, cameras, batteries, memory, and other important specifications and features to easily choose the right phone for you. Our goal is to help you uncover differences between the products and find the phone that will best fit your needs.
| DESIGN AND DIMENSIONS | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Product Type | Smartphone | Smartphone | |
|---|---|---|---|
| Manufacturer Model Number | ZX551ML | - | |
| Form Factor | Touch | Touch | |
| Height | 158.9 mm | 165.2 mm | Realme C21 has greater height than ASUS ZenFone Zoom (ZX551ML). |
| Width | 78.8 mm | 76.4 mm | ASUS ZenFone Zoom (ZX551ML) has greater width than Realme C21. |
| Depth | 12 mm | 8.9 mm | Realme C21 is narrower than ASUS ZenFone Zoom (ZX551ML). |
| Weight | 185 g | 190 g | ASUS ZenFone Zoom (ZX551ML) is lighter than ASUS ZenFone Zoom (ZX551ML). |
| Body Colour | Ceramic white | Pure black | Cross black | Cross blue | |
| Waterproof (Water-resistant) | - | - | |
| SAR Value | 0.432 W/kg (body), 0.343 W/kg (head) | - | |
| Connector Type | Headset jack - mini-phone 3.5mm Micro-USB - 5 pin Micro-USB Type B |
Micro-USB Headset jack - mini-phone 3.5mm |
|
| SIM Card Type (Size) | Micro SIM | Nano SIM | |
| SIM Card Qty | - | Dual-SIM |
| DISPLAY | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Display Type | LCD display | LCD display | |
|---|---|---|---|
| Display Technology | IPS | LCD | |
| Screen Size (Display Size) | 5.5" | 6.5" | Realme C21 has larger screen size than ASUS ZenFone Zoom (ZX551ML). |
| Screen Resolution (Display Resolution) | 1920 x 1080 pixels | 1600 x 720 pixels | ASUS ZenFone Zoom (ZX551ML) has better screen resolution than Realme C21. |
| Display Format | Full HD | HD+ | |
| Pixel Density | 401 ppi | - | |
| Aspect Ratio | - | 20:9 | |
| Max Brightness | - | 420 cd/m² | |
| Colour Depth | 16.7 million colours | - | |
| Display Features | - | Mini-drop display | |
| Display Protection (Screen Protector) | Corning Gorilla Glass 4 (scratch resistant glass) | - |
| PROCESSOR | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Processor Type (CPU) | Intel Atom | MediaTek Helio G35 | |
|---|---|---|---|
| Processor Number | Z3590 | - | |
| Clock Speed | 2.5 GHz | 2.3 GHz | ASUS ZenFone Zoom (ZX551ML) has higher clock speed than Realme C21. |
| Processor Core Qty | Quad-core | 8-core | Realme C21 has higher processor core quantity than ASUS ZenFone Zoom (ZX551ML). |
| Graphics System (GPU) | PowerVR G6430 | PowerVR GE8320 |
| MEMORY | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| RAM | 4 GB | LPDDR4X SDRAM - 3 GB | ASUS ZenFone Zoom (ZX551ML) has more RAM than Realme C21. |
|---|---|---|---|
| Internal Memory Size (Storage Capacity) | 32 GB | 32 GB | Both phones have the same internal memory capacity. |
| Supported Flash Memory Cards (Expandable Memory) | microSDHC, microSDXC - up to 128 GB | microSD |
| CAMERA | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| MAIN CAMERA |
|---|
| Number of Main Cameras | 1 | 3 | |
|---|---|---|---|
| Sensor Resolution | 13 Megapixel | 13 Megapixel | Both phones have the same camera resolution. |
| Lens Aperture | F/2.7-4.8 | F/2.2 | Realme C21 has better lens aperture than ASUS ZenFone Zoom (ZX551ML). |
| Lens Construction | - | 5-element | |
| Optical Image Stabiliser (OIS) | Optical Image Stabiliser (OIS) | - | ASUS ZenFone Zoom (ZX551ML) has optical stabilisation. |
| Focus Adjustment | Automatic | Automatic | |
| Laser Auto Focus | Yes | - | |
| Digital Zoom | 3x | 4x | Realme C21 has better digital zoom than ASUS ZenFone Zoom (ZX551ML). |
| Special Effects | - | HDR | |
| HDR Mode | Auto HDR mode | - | |
| Camera Modes | Panorama | Panorama, Time-lapse mode, Slow motion mode, Beauty mode, Expert Mode, Nightscape capture mode, Portrait, Filter mode, Super nightscape | |
| Face Recognition (Face ID) | Face detection | - | ASUS ZenFone Zoom (ZX551ML) has face detection. |
| Light Source | Dual LED flash | LED flash | |
| Video Resolutions | 1920 x 1080 (1080p) | 1920 x 1080 (1080p) at 30 fps | |
| Camera Features (Functions) | - | Phase Detect Auto-Focus (PDAF), AI Triple camera, Chroma boost |
| SECOND CAMERA |
|---|
| Sensor Resolution (2nd Camera) | - | 2 Megapixel | |
|---|---|---|---|
| Lens Aperture (2nd Camera) | - | F/2.4 | |
| Lens Element Qty (2nd Camera) | - | 3-element | |
| Camera Functions (2nd Camera) | - | B&W lens |
| THIRD CAMERA |
|---|
| Sensor Resolution (3rd Camera) | - | 2 Megapixel | |
|---|---|---|---|
| Lens Aperture (3rd Camera) | - | F/2.4 | |
| Lens Element Qty (3rd Camera) | - | 3-element | |
| Camera Functions (3rd Camera) | - | Macro camera | |
| Camera Features (3rd Camera) | - | 4cm macro photography |
| FRONT CAMERA |
|---|
| Number of Front Cameras | 1 | 1 | |
|---|---|---|---|
| Sensor Resolution (Front) | 5 Megapixel | 5 Megapixel | Both phones have the same front camera resolution. |
| Lens Aperture (Front) | F/2.0 | F/2.2 | ASUS ZenFone Zoom (ZX551ML) has better front lens aperture than ASUS ZenFone Zoom (ZX551ML). |
| Lens Element Qty (Front) | - | 3-element | |
| Special Effects (Front) | - | HDR | |
| Camera Modes (Front) | - | Time-lapse mode, Beauty mode, portrait mode, AI Beauty, Filter mode, Panoramic mode | |
| Face Recognition (Face ID) | - | Face recognition | Realme C21 has face detection. |
| BATTERY AND CHARGING | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Battery Capacity (Battery Size) | 3000 mAh | 5000 mAh | Realme C21 has larger battery capacity than ASUS ZenFone Zoom (ZX551ML). |
|---|---|---|---|
| Battery Technology | Lithium polymer | - |
| CELLULAR | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Technology | WCDMA (UMTS) / GSM | WCDMA (UMTS) / GSM | |
|---|---|---|---|
| Mobile Broadband Generation | 4G | 4G | Both phones have the same mobile network generation. |
| Operating System | Android 5.0 (Lollipop) | Android 10 | |
| User Interface | ASUS ZenUI 2.0 | Realme UI | |
| Navigation | A-GPS, GLONASS, BeiDou | GPS, A-GPS, GLONASS, BeiDou |
| COMMUNICATIONS | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Data Transmission | GPRS, EDGE, HSDPA, HSUPA, HSPA+, LTE | FDD-LTE, TDD-LTE | |
|---|---|---|---|
| 2G Band | 850 GSM, 1800 GSM, 1900 GSM | 850 GSM, 900 GSM, 1800 GSM, 1900 GSM | |
| 3G UMTS Band | - | Band 1, Band 5, Band 8 | |
| 3G UMTS Frequency | - | 2100, 850, 900 | |
| 4G LTE Band | Band 1, Band 2, Band 3, Band 5, Band 7, Band 8, Band 9, Band 18, Band 19, Band 28 | Band 1, Band 3, Band 5, Band 7, Band 8, Band 20, Band 28, Band 38, Band 40, Band 41 | |
| 4G LTE Frequency | FDD 2100, FDD 1900 PCS, FDD 1800+, FDD 850, FDD 2600, FDD 900, FDD 1800, FDD 800 lower, FDD 800 upper, FDD 700 APT | FDD 2100, FDD 1800+, FDD 850, FDD 2600, FDD 900, FDD 800 DD, FDD 700 APT, TDD 2600, TDD 2300, TDD 2500 | |
| Wireless Interface | IEEE 802.11a/b/g/n/ac | IEEE 802.11b/g/n | |
| Bluetooth | Bluetooth 4.0 | Bluetooth 5.0 | |
| Bluetooth Profiles | A2DP | - | |
| NFC | Yes | - | ASUS ZenFone Zoom (ZX551ML) has NFC reader for mobile payments. |
| Messaging Services | SMS, MMS | - |
| FEATURES | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Phone Functions | Speakerphone, call timer, conference call, vibrating alert | Speakerphone, voice control, call timer, conference call, flight mode, voice dialing, vibrating alert | |
|---|---|---|---|
| Sensors | Accelerometer, proximity sensor, digital compass, gyro sensor | Accelerometer, proximity sensor, magnetometer, light sensor | |
| Security Devices | - | Fingerprint reader | |
| Additional Phone Features | Multitasking | Super power saving mode, HyperEngine technology, Reverse charging |
| OTHERS | ASUS ZenFone Zoom (ZX551ML) | Realme C21 |
|---|
| Included Accessories | Power adapter | USB cable, power adapter, SIM card removal tool | |
|---|---|---|---|
| Compliant Standards | - | TUV Rheinland |
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