Iphone - manual control apps

I got hold of one called slow camera. Didnt really do a great job, I wanted it for traffic trails.
After a bit of research I discovered that the longest shutter speed is 1/3 of a second...... All the apps with long exposure do is stack a series of 1/3 exposures together thus totally useless really for traffic trails.
Just some info I wanted to pass on.
After a bit of research I discovered that the longest shutter speed is 1/3 of a second...... All the apps with long exposure do is stack a series of 1/3 exposures together thus totally useless really for traffic trails.
Just some info I wanted to pass on.