Use of "as far as something/someone is concerned"

Question

1. I make the decisions as far as finance is concerned.
2. Where spelling is concerned, he’s never been a strong student.
3. There’s no reason to wait, as far as I’m concerned.
4. So far as those big companies are concerned, we're just another little company that they can step on.

The first two sentences have been taken from the dictionary of Macmillan Publishers Limited, and the last two from Cambridge Dictionary. All these sentences have been used to explain the meanings of as far as something/someone is concerned. But in the second sentence only the word concerned has been used; as far as... has not been used. Please tell me why. Where as far as can be omitted?

Though these dictionaries explained the meanings of as far as something/someone before giving the examples stated above, I couldn't not understand it properly. It would be better if I got other alternative ways to rewrite above sentences. It would help me a lot. Please suggest the alternative ways to rewrite them.

Thanks!

Answer 1

Your second sentence is just an alternative way of phrasing the sentence. It could equally be written as either of:

As far as spelling is concerned, he’s never been a strong student.
He’s never been a strong student as far as spelling is concerned.

The "where" and the "as far as" can be treated as synonyms. You could equally use where in your other three sentences.

You say that your first two sentences are from the same source. That source is showing you the equivalence of the two forms.

Answer 2

I partly agree with Chenmunka's answer, but not wholly.

I think there are two different meanings for as far as X is concerned, and you can replace as far as by where in one of them, but not the other.

In the first two examples, the 'X' is a subject that the sentence is about (I don't mean 'subject' in the grammatical sense: grammarians would call this a topic). It is typically an inanimate, or even an abstract, as in these examples; but it could be animate, as in "As far as cats are concerned, a vegetarian diet is not an option". It is not usually a sentient being (such as a person), because that might be ambiguous with the second meaning. The expression can be interpreted literally, and paraphrased with where.

The second meaning, in your third and fourth examples, has a sentient (usually human) 'X', and it means "from X's point of view" or even "only taking regard to X's preferences". In this use it is an idiom, and you can't replace as far as with where.