Does dodging have invincibility frames?

When dodging, does it have any invincibility frames(you cannot be hurt during certain "frames" of the dodge)?

Do different weapons have a different amount of frames?(if they have invincibility in the first place)

where are these frames (if any)? start of the dodge? or towards the end?

Yes, dodging does give a small number of invincibility frames. I believe the number is around 2 or 3? All weapons have the same number of invincibility frames. The armor skill Evasion increases how many invincibility frames you get.

In previous games, Evasion increased the number of invincibility frames in the following manner:

• +1: 8 frames
• +2: 10 frames

In MH4U, you can get Evasion +3, but I'm not quite sure how many more invincibility frames it gives you.

expanding on Yuuki answer: at evade +1 you get around 1/4 of a sec invincibility at evade +2 you get 1/3 of a sec at evade +3 you get around a bit more of 1/2 of a sec

note that this is only when you roll, or side step when using bow/lance. and this happens only at the beginning-mid of the roll/sidestep.

it is kind of broken, since the sidestep is faster than a roll, and you can do a second sidestep right after finishing the first one, sidestepping will clearly show that you have evade+3 as you will be almost all the time of the sidestep invincible if you sidestep fast enough.