This is the reason why people never smiled in old photographs

Whenever you see an old-timey group photo, the subjects always look moodier than a teenager at a garden centre.

And before today, we put it down to the past being a bit rubbish. After all, they didn't have the internet, or Soccer Saturday, or McDonald's chicken nuggets - they had every right to be angry.

But according to Vox.com, there's a far more reasonable explanation for the phenomenon. According to camera heads, retro cameras' long exposure times meant that shooting photos took minutes at a time. People couldn't hold their smiles for that long, and it would have inevitably led to blur. 

The steely-faced look was also influenced by classic paintings, amongst other things. Check out the video below for the full explanation...