Forgot to photograph some bouncers and little sisters, any idea if I'll miss on their achievements?

[Scooter]

Basically, I've photographed every bouncer, rosie and little sister since getting the camera, got to Fort Frolic and forgot to photograph the 3 ones there. I got the little sister after she was rescued and a bouncer after I killed out.

As much as I like Bioshock, I have a hard time playing it because it feels rather old and it's pretty frightening at times, I want as many achievements as I can possibly get because I like 100%ing games, I might not 100% Bioshock, but it'd be nice to have a lot of the progress in case I want to.

[Kai]

Dificult, don't you have a save prior to that?

[Lukey Pooky]

there might be a bouncer lumbering around in the medical pavilion. it's not the highest level one, the early variant i think.

[Crypto Gamer]

You can go back to earlier lvls in bio 1,so go back to Medical or the Fort and photo bouncers,kill them once they no longer give photo points and they will respawn in time even if no sister left on that lvl so you can "photo farm" them.

About little sisters they are limited,and you can only gain limited research from one.However every few minutes a big Daddy will escort a sister back into a vent and eventually will knock on a vent and "summon her" again.
The newly appeared little sister count as"new"for the purposes of camera research.Of course the lvl must have at least 1 little sister left,or none will appear from the vent.

[Scooter]

I have saves prior but I'd rather not restart. Following Crypto Gamer's advice, it really shouldn't be a problem.