React-native iOS app crashes when taking picture

I am using react-native-camera module in my app. Followed instructions to setup Camera using documentation listed here. After the setup, I can see camera in iOS simulator and also on my iPhone. But when I click on CAPTURE button, my app crashes in simulator and I get following error on my iPhone:

Here is the code :

import React from 'react';
import {  Text, StyleSheet } from 'react-native';
import Camera  from 'react-native-camera';

class NCamera extends React.Component {
    takePicture() {
        alert('Pressed');

        this.camera.capture()
            .then((data) => {
                console.log(data);
            })
            .catch(err => console.log(err));
    }
    render() {
        return (
            <Camera
                ref={(cam) => {
                    this.camera = cam;
                }}
                style={styles.preview}
                aspect={Camera.constants.Aspect.fill}>
                <Text style={styles.capture} onPress={this.takePicture.bind(this)}>[CAPTURE]</Text>
            </Camera>
        );
    }
}

Please note, if I remove capture method (code below), the app does not crash and works fine both in simulator and iPhone. So there is definitely some problem with the code below which I am not able to figure out what.

this.camera.capture()
            .then((data) => {
                console.log(data);
            })
            .catch(err => console.log(err));