Are there different sounds for the fathah?

EsSelamu alejkum

mashaAllah, this is a beautiful and a very useful site, may Allah bless you and reward you for your efforts.

I have a question concerning the propunciation of fatha. I have learned to make a difference between fetha when it is on 'hard' letters (like q, da, ta,) on one hand, and when it is on the 'soft' letters (lika ba etc,, on the other).

What I mean is that in the first case I pronounce it as an 'a' whereas in the second case I pronounce it as an 'e' (not like an English (i) but as an short a/e like in the name Esmaa)).
And this is what I can hear when I listen to different qarias, but I have now heard that this distinction is wrong. Can you please help me on this?
Examples to help you understand what I mean:
fetha as an 'a': 'Rahiim', 'Rahmaan', 'darabe'
but I say fetha as an 'e' in: 'rejul' 'fejr' 'emiir'.

Isn't this fusha? Is it a dialect? I'm a non-arab.

Hope it is not confusing and you get my point.
EsSelamu alejkum we rahmetullahi we berekatuhu.
Wa alaikum assalaam wa rahmatullahi wa barakatuh. Jazakum Allahu khairan for your dua’.
For most letters, the fathah has one sound, the only time the fath has a different sound is when it is on a letter that has tafkheem, meaning one of the letters in the group  ,  the letter  ,  and the letter  of the Glorious name of Allah when it has tafkheem. Tafkheem is an Arabic word, translated as velarization. It means a heavy sound that fills the mouth with an echo, so when the letter has tafkheem, the accompanying fath on it, also acquires the tafkheem. 

Other than these cases, all the fathah of each letter should sound the same. Some of the examples given in the question are of the letter with a fathah, which has tafkheem, but the other letters in the examples do not have tafkheem, so the fathah on these other letters should all sound the same.
Insha’ Allah this helps you understand. 
Wa assalaam alaikum wa rahmatullahi wa barakatuh.