My I phone has a front and back side camera. I have a screen protector on the face that affects the readings. I make sure I use the back side camera for most accurate results with this app. Can’t speak to accuracy compared to a standard. This app works great for my needs.

Do not expect customer service to ever answer any questions or emails.Light levels are absolute levels of brightness. Therefore, it's very odd that there is an indoor/outdoor button to set. The two settings get very different readings. Why? It should not matter whether the reading is indoors or outdoors. The number is simply a function of how bright it is.Other apps on the App Store will also tell you what the color temperature of the light is. That can be very useful in knowing whether it's bluish or yellow-ish. This app does not give you that.

I spent over 60 years in electro optical engineering, and this is by far the best two dollars I ever spent. I agree the color temperature would be a big plus, and to be able to see the image would be very helpful to get things pointed the right way.

Disregard any negative comments! From an app developer standpoint I appreciate the effort put into this app. For reading light values from a camera, this is very accurate. Buying this app you have to know that it's coming from an iPhone, not a comercial light meter! Great job!