Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_79373 ( "Brand" text, "Product Name" text, "Focal Length" text, "35mm EFL and equivalent aperture" text, "Max. aperture" text )

### Question ###
What is the brand of the Sigma 30mm f2.8 DN, which has a maximum aperture of f /2.8 and a focal length of 30mm?

### Accurate SQL ###

SELECT "Brand" FROM table_79373 WHERE "Max. aperture" = 'f /2.8' AND "Focal Length" = '30mm' AND "Product Name" = 'sigma 30mm f2.8 dn'