In the past few years, we have covered plenty of light meter apps for iPhone that can help you capture better quality photos. Luxi for All is also worth a look. It turns your iPhone into a light meter. It combines with the Luxi app to help you determine the best settings for your DSLR camera.
You can use this tool to set the right light color temperature and level for your shoots. Simply download a compatible app, attach the device to your phone, and you are ready to measure your light level.[where to get it]