I managed to participate on some days last year and found it both limiting and liberating. My aim is to do every day this year. I'll be using my 30mm lens on my Sony a6000 as the closest to full frame 50mm lens - for starters, just have to keep that horizon straight in every shot!
PS I might have a go at Richard' challenge but I only have a 16-300 zoom, not a standard lens. I can try setting it 50 every time and see how I go maybe?
Yes, setting 50mm should work OK: + or - a mm or two would not be a disaster!
Gorgeous colours here