Using Case and field format

Hi All

I have a field (subjective) that can contain numbers or text.

What I am trying to do is create a calculated field that shows a 1 if subjective begins with a 4 and show 2 if it doesn't.

I have tried

CASE
WHEN left(f.subjective,1),= '4' THEN 1
else 2
END AS CalculatedPrice

I get the error "An expression of non-boolean type specified in a context where a condition is expected, near ','"

If I try

CASE
WHEN cast(left(f.subjective,1),varchar(50)) = '4' THEN 1
else 2
END AS CalculatedPrice

I get the error "'varchar' is not a recognized built-in function name"

Similar if I try nvarchar.

Thanks