"capacity of" vs "capacity as"

[Guest]

which is better or correct?

In my current "capacity of" Assistant accountant....

In my current "capacity as" Assistant Accountant...

[Conchita]

The following are correct constructions:

In my current capacity as Assistant Accountant.

This room has a sitting capacity of thirty.

The police have the capacity to deal effectively with crime.

I have no capacity for concentration at the moment.

And:
He is capable of really hard work.

[Guest]

thank you for your explanation.