Lenovo Vibe K4 Note
detailed specifications
GENERAL
Release date -January 2016
Form factor -Touchscreen
Dimensions (mm)- 153.60 x 76.50 x 9.10
Weight (g) -158.00
Battery capacity (mAh) -3300
Removable battery- No
SAR value -NA
DISPLAY
Screen size (inches) -5.50
Touchscreen -Yes
Resolution -1080x1920 pixels
Pixels per inch (PPI) -403
HARDWARE
Processor make -MediaTek MT6753
RAM- 3GB
Internal storage- 16GB
Expandable storage -Yes
Expandable storage type- microSD
Expandable storage up to (GB) -128
CAMERA
Rear camera -13-megapixel
Flash -Yes
Front camera- 5-megapixel
SOFTWARE
Operating System Android- 5.1
Skin Vibe -UI
CONNECTIVITY
Wi-Fi- Yes
Wi-Fi standards supported -802.11 a/b/g/n/ac
GPS -Yes
Bluetooth -Yes, v 4.00
NFC -Yes
Infrared -No
USB OTG -No
Headphones -3.5mm
FM -Yes
Number of SIMs -2
SIM 1
SIM Type -Micro-SIM
GSM/CDMA -GSM
3G -Yes
4G/ LTE- Yes
Supports 4G in India (Band 40)- Yes
SIM 2
SIM Type -Micro-SIM
GSM/CDMA -GSM
3G -Yes
4G/ LTE -Yes
Supports 4G in India (Band 40) -Yes
SENSORS
Compass/ Magnetometer -Yes
Proximity sensor -Yes
Accelerometer- Yes
Ambient light sensor -Yes
Gyroscope- No
Barometer- No
Temperature sensor -No

As I already told in first impression of Lenovo vibe K 4 note that it is the powerful note ever, it is also observed by buyer. There is recorded 2 lakh phones are registered on amazon.in in first sale.
Lenovo had made a tremendous starting of new year by its killer note. The popularity of K 3 note can be determined by the fact that in year 2015 it is third largest  searched phone on Google. After this huge success if K3 note there is very large expectation from K4 note. There are many big difference between K3 note and K4 note. Lets see weather the K4 note stands on our expectations or not

Look and Design
The first very big difference between K3 note and Vibe K4 note is its design. K3 note is flat and its design is like is old modal but Vibe K4 note is curved modal phone just like other modal Motorola. These curved modal are so popular because of these phones are easy to handle in one hand of such large screen.
The front panel contains the 5.5 inch screen. The best part is there is very less wastage in the front. The screen covers almost whole front. The design of this phone strongly resembles like Moto E . The edges are rounded by golden colored ribbon which looks pretty good. There is front camera on top right side of phone.  The volume controller buttons and power button lie on the right side of the phone.
Coming to the back panel of the phone, as I already told that this phone strongly looks like Moto E , this point also true for back panel also. In Moto E there is lack of fingerprint sensor so in that phone the flash lie just below the camera but K 4 note there is the fingerprint sensor that lie just below the camera and the flash lie on the just right of the of the camera. Below that there is company’s new logo which looks nice but according to me its old design looks better. Because of the curved back design helps to hold phone comfortable and help in typing by one hand. Overall design is good but not the best.

Display
The Vibe K4 Note has the same 5.5-inch display as in K 3 note with a resolution of 1920 by 1080 pixels and a pixel density of about 400 PPI.  It has 450 nits of brightness. It is bright, offers vibrant and sharp color output. It has sharp display and very good viewing angle. Even though the display is glossy, it doesn’t attract fingerprints easily. It also has Corning Gorilla Glass 3 protection to prevent the display from scratches. The display is very very good in low light but in sunlight sometimes when you see it great concentration it looks a little fade. Avoiding this problem overall display is very good.

Specifications
Lenovo vibe K4 note packs with 1.3 Ghz 64 bit Mediatek MT6753 which is super for mid range phone. This will provide premium mobile experience at cheaper price range which is little lower than K3 note. Company had made an improvement in RAM, as it contains 3GB RAM. It contains an internal memory of 16 GB which can be extended up to 128GB by microSD cards.
Vibe K4 note also support NFC (near field communication technology). This impressed us up to great extent because it is cheapest phone till today which support NFC. Additional hardware contain accelerometer, gyroscope, proximity sensor, and magnetometer.

Software
The smartphone runs on Android 5.1 (Lollipop) with Lenovo’s own Vibe UI on top. This thing unexpected because saveral phone like Nexus are already launched with 6.0 Marshmallow.  Android Lollipop brings several new features, including Material design, Multi user support, battery saver and lots more features. The company has not announced when it plans to roll out the Android 6.0 (Marshmallow) update for the smartphone. It include saveral new features in quick setting option like Secure Zone, Flashlight, Cast Screen, Wide Touch and Super Power. It also has brightness adjustment. An interesting feature is that you can if you want edit notification bar icons . You can launch the dialer or the camera directly from the lockscreen.
It has Wide Touch option that lets you create a floating bar for accessing utility apps like camera, music, calculator and more. Smart scene lets you create scenes for different time period or places. Apart from regular Google Apps it comes with some other apps like Facebook Gamestore Gureva music McAfee security ( not in K3 note) Shazam, Skype, Step Counter, Truecaller, Twitter, WeChat, UC Browser, WeChat, WPS Office, and Tap the Frog HD game.

Camera
Lenovo K4 Note features a 13 MP rear Isocell camera with face detection Auto Focus and Dual tone LED flash. The face Detection technology helps the camera to lock the focus quickly depending on whether the subject is in phase or out of phase. The rear shooter comes with with Samsung S5K3M2 ISOCELL sensor with 1.12 um pixel size, PDAF, an aperture of F/2.2 which will enhance the shooting capabilities.
On the front there is a fixed focus 5 MP camera for capturing selfies and video chats. This combination of 13 MP and 5 MP has become the trademark of the current mid range segment with almost all budget smartphones sporting the same 13 MP and 5 MP camera combination with a few exceptions.
Lenovo had done some experiments in Camera Ui. Camera Ui is little bit different from what we have seen earlier on other Lenovo smartphones in the past. It seems like Lenovo has reduced the shooting modes on this camera that were earlier part of the arsenal on earlier Lenovo smartphones. The camera UI is very simple with well placed controls and you can swipe between photo and video shooting modes without breaking a sweat. The UI is fast, smooth and works flawlessly without any disturbances. The menu option lets you choose Panorama and also has several Effects (Mono, Sepia, Negative, Memory, Gorgeous, Elegant and Cool). The one disappointing thing is there is no new effect added extra i.e. there are same effect as that in K3 note. Settings option lets you choose aspect ratio (16:9, 4:3 and 1:1), adjust white balance, ISO (100 to 1600), enable geo location, option to use volume button as a shutter key and more.
Now coming to quality. The images that we seen  using this smartphone indicates that the camera on this smartphone is improved that from K3 note and it is the best if not the best that we have seen so far on budget smartphones in the same price bracket. Despite all the good and awesomeness packed into this smartphone there are some shortcomings with the camera module that we observed.
The shutter speed in HDR mode was a little slow and this is not much of a flaw but we observed this. The images in low lighting conditions come out be very good looking with ample details and noise free but refresh rate was not that great. The front camera works just fine and clicks descent selfies without any issues so far. But if you are one of those smartphone photographers who love to take huge amount of photos with their phones then you will be a little bit disappointed.

Performance
Coming to performance, it packs with an Octa-Core MediaTek MT6753 processor with eight ARM Cortex A53 CPUs clocked at 1.3GHz per core and 3GB of RAM. Performance. As we know that if any phone contains its own UI then it consume large RAM but its performance is very good. Multitasking is smooth due to 3 GB RAM present in the phone. Some of my team member say that it gets a little warm, but l did not face any heating issues during playing big games like Asphalt 8 or 4G use.
The Lenovo Vibe K4 Note comes with a feature called TheaterMax which, as per company's claim, can convert regular content to its immersive VR counterpart. This feature as per our use works nicely. This is Powered by Lenovo Virtual Reality (VR) technology, the idea is to give users a virtually large screen cinematic experience. It should work with any virtual reality headset. The Lenovo K4 Note also comes equipped with two front-facing speakers (1.5W each) alongside Dolby Atmos audio. Coming to fingerprint sensor it works very accurate but you feel some problems with wet hands. You can store two fingerprint but some phone give option of 5.
It doesn’t have a separate music player, so you have to use Google Play Music. It can play a range of audio formats and it has FM Radio with recording. Thanks to Dolby Atmos, Wolfson WM8281 audio codec and dual front-facing speakers, loudspeaker output is brilliant and clear even in full volume. It has 4G support with support of 4G LTE bands (TDD B40 2300MHz and FDD B3 1800MHz) for India. Both the SIMs support 4G, but you can enable 4G only in one SIM at a time, while the other goes to 2G. You can set the default SIM for voice call, messaging or data connection. It scored 34833 points in the AnTuTu Benchmark 5 and lies behind the Vibe P1. It managed to score 6856 points in the 3DMark Ice Storm Unlimited GPU benchmark. It managed to score 779 points in the Basemark OS II benchmark.

Battery
Coming to the battery life, the 3300mAh (Rated) / 3400mAh (Typical) built-in battery doesn’t offer good battery life.  It lasted for 14 hours and 05 minutes in our talk time test. Coming to browsing test it last up to 5 hr and 30 mins. It lasted for 10 hours  in our Video Playback test. It takes very large time to charge completely as it does not contain any fast charging feature which is disappointing.

Conclusion
K4 note is very impressive phone in this price segment as it has great performance better software bit some people does not love its battery performance. If you can increase your budget a slight more then Lenovo Vibe p1 van be a better option. In my sense there is no phone till now which be a good alternative of Vibe K 4 note.