After 3 hours and brown liquid drops?
If you want to know, you can go to the local material market lighting shop to have a taste.
You don't need TTL at all. The design inside doesn't need too many automatic functions to interfere, because you can adjust the output level, and then you can control the distance of lights artificially. Other functions, such as modeling light lamps, are actually supplementary.
In fact, these are the main, and there will be no function, because indoor flash, relative to the set top flash is large, the purpose is to let people use light, light control, serious photography.
