How to set image resolution with QCamera in Qt 5.3?

I am working on Qt Qcamera to capture images, on Windows Surface Pro tablet. I have written this small piece of code to check the QCamera functionaliy, but after capturing the image, the image saved has very low resolution i.e. 640*360, even though the rear camera of surface pro supports 1280*720. Even the QList for supported resolution always returns empty. I looked everywhere but couldn't find a possible solution, can anyone please help?

Here is the code I am using:

#include "camera.h"
#include <QCamera>
#include <QCameraImageCapture>
#include <QCameraViewfinder>
#include <QDebug>
#include<QMultimedia>

Camera::Camera(QWidget *parent) :
    QWidget(parent)
{

    QByteArray cameraDevice;
    int count = QCamera::availableDevices().count();

    int cameraId = 1;


    QList<QByteArray> cameradev = QCamera::availableDevices();
    QByteArray camdevice = cameradev[cameraId];

    QCamera *camera = new QCamera(camdevice);

    QString description = camera->deviceDescription(camdevice);
    qDebug() <<"Device Name"<< description;

    QCameraViewfinder *viewfinder = new QCameraViewfinder();
    viewfinder->showMaximized();
    camera->setViewfinder(viewfinder);
    QCameraImageCapture *imageCapture = new QCameraImageCapture(camera);
    //camera->setCaptureMode(QCamera::CaptureStillImage);
    camera->start();
    QList<QSize> resolutions = imageCapture->supportedResolutions();//returns       always empty
    QImageEncoderSettings imageSettings;
    imageSettings.setCodec("image/jpeg");
    imageSettings.setResolution(1280, 720);
    imageCapture->setEncodingSettings(imageSettings);
    imageCapture->capture("D:/1.jpg");
    camera->searchAndLock();
    camera->unlock();
    qDebug() << camera->error();    
}

Well it seemed the problem was with Qt version, this problem is fixed in Qt 5.5 version and above and it's possible to get all supported resolutions of a camera.