You have probably heard about this a lot and understood the importance of light when photographing. You have probably also looked at your own pictures taken from mid day and seen the bright light coming straight from above creating hard shadows and extreme contrast. Then you look at the pictures taken closer to sunset or just after sunrise and you see something quite different. You see warm light coming in from the side, soft shadows and less contrast. The pictures have this magic golden glow all over. So we call this two periods in each day for the golden hour. A little misleading, because depending on where you are, it is seldom an hour. Sometimes it is just 15 minutes and sometimes it can be a lot longer than an hour. Photographing outdoors you want to know exactly when this happens and for how long – and exactly at the site you are. So of course you have apps from app store. I use two different ones. You only need one, but I have both and use them a little differently.
The TPE is very advanced and you can plan very precise when and where the light will appear and disappear. You can easily plot in the position and plan every detail. It is a lot of options and menus but you get the basics fast and this is really all you need.
I just like the easy user interface from the app called Rizon. It is super easy and if you just need a quick answer I usually open this one.
They are both good but very different level of features. Enjoy.