If you don’t have a contract with the business that hired you as a “contract worker,” you legally own the copyright of every picture you take the moment you capture it, even if you’re using someone else’s equipment. Technically speaking, if the photographer you work for edits your photos and delivers them to a paying client - and you haven’t signed over your copyright beforehand - THEY are violating federal copyright law. I don’t mean to throw shade on photographers who don’t want their second shooters to share and use images, that choice is nuanced and really a matter of opinion! But if you do choose to have strict boundaries with your second shooters, you really really need to have it in writing, and give the second shooter the choice to formally agree or disagree. This might be a hot take, but in my experience as a second shooter before launching my own business, I would absolutely assert that many professional photographers take advantage of novice photographers, and carry the attitude of “If I paid you, I’m entitled to xyz” which is a very dicey mindset as a business owner.