Hi,
Your settings are fine:
frame size: 1280×720
pixel aspect radio: square
editing timebase: 50
compressor: apple pro res 422
How are you converting your footage to ProRes?
You can choose 25fps as your editing timebase. This is not ideal as 50fps is usually shot for slo-motion footage post conform, but you’ll have to make do and tweak your audio (if it was recorded separately) when it appears to drift off sync.
ProRes LT is fine for most DSLR footage. Make sure your Render Codec and Sequence codec are the same. If after doing this, your footage still appears substandard and pixellated, check your RT settings.
Sandeep.