Studio quality describes a lighting setup, not a place

It is the most used phrase in this category and the least examined. Splitting it in two makes it useful.

The half that is reproducible

Controlled light and a controlled background. Neither is mysterious: a main source at eye level rather than from the ceiling, a surface behind the subject that separates from their hair colour, and distance between the two so the background goes slightly soft.

That is geometry rather than equipment, and geometry travels.

The half that is not

A person looking at you who says your chin is slightly too high, or that your shoulders look tense. That feedback loop is the actual product of a studio session, and no process reproduces it.

Which half you need

For one important headshot, the second — and it is frequently worth the whole fee.

For forty portraits across people hired in different months, the first, because the problem there is a calendar rather than a critique. No amount of expert direction solves the fact that there is no day on which everyone is available.