Re: What if I object?
Not strictly true.
For a subject access request to be valid you have to provide sufficient details to allow the data controller (DC) to identify the relevant personal data so any request for 'all of may data' regardless of media/format can be refused.
Just saying a specific date isn't enough as those cameras could be running 24/7 so a time frame would be a reasonable clarification from the dc.
Also when providing the data a permanent copy doesn't have to be provided if it would require disproportionate effort to provide it but the dc would still be required to allow the requestor to view the footage.
When it comes to the images of 3rd parties most councils in my experience just blur faces (although there is a technical DP argument that the images aren't personal data if the council and the requestor don't have sufficient information to identify the individual).