Filter cap needed on regulated supply?

retrolefty:
Why not just connect the 12 volt to the arduino external power connector or Vin pin?

I need more 5V current than the Arduino can supply - the project has a seven-segment display as well as a few LEDs. Also the LED driver (NXP PCA 9622) needs VCC as well. I have room for the 7805 so will have a bit of reserve...