25 or 50 fps?What is the best practice to documentary?

Hi, i shooting a european documentary.What is the fps best practice to delivery? 25p or 50p fps?

Which delivery platform? If for TV, ask the station.
In case you may ever need slo-mo, 50 fps is giving you the flexibility. It’s very easy to drop every other frame in DR for regular speed in 25.
If for the internet, 30 might be better, but watch your exposure time under artificial light.

What is the fps standard for european broadcast television?What is the fps standard for european cinema festival?

European broadcasters require 1080i50 (but you can also deliver 25p packaged as pseudo 50i).

For best flexibility in post I would recommend shooting in 50p.

Festivals should be able to playback any framerate supported by SMTP DCP standard, which includes 25p.

What is the fps standard for european broadcast television?What is the fps standard for european cinema festival?

All the mainstream broadcasters in Europe run 1080/50i (aka 1080/i25) internally - even those that broadcast 720/50p or 1080/50p at the moment. If you shoot 1080/25p some will accept a delivery in 1080/25p - but most will require this delivered as 2:2 1080/50i (and many will require closing rolling / crawling credits rendered in 50i not 25p if that's their standard to avoid motion judder) (Some are now accepting 1080p and 2160p masters at 25p and 50p for online streaming - BBC iPlayer is 2160/25p delivery for UHD HDR productions for instance)

You should be shooting 25p or 50p in Europe to avoid mains lighting flicker (24fps and 30/60fps can give you nasty flicker with some discharge and LED lighting like street lights, sports stadium lighting etc.).

Most mainstream documentaries shot for European TV are shot predominantly in 25p with 180 degree (i.e. 1/50th second) shutter for their sync stuff, with people sometimes shooting non-sync 'over cranked' stuff at 1080/60p (outside in daylight) or 1080/50p (if 50Hz lighting is going to cause flicker at 60fps) for smooth slow motion (natural history is a good example of this - as it stretches short moments of interesting footage out for longer).

(If you shoot 50fps with 360 degree shutter (i.e. 1/50th second) then you can discard alternate frames in post and have video that looks identical (or near identical) to video that you'd shot at 25fps with 180 degree shutter (the same 1/50th second exposure) but you'll use twice the storage. If you use this footage slowed down it will have a different look to 50fps shot with a 180 degree/1/100th second shutter - but it still looks nice as it has the same motion blur as regular 25fps 180 degree stuff)

The 25fps look is near-standard these days for docs - very few people are shooting 50i or 50p realtime for the 'video' look (50i native recording is increasingly difficult on many cameras).