You only have to finish 20 jobs for this achievement. There are about 40 jobs available to take on. There are many jobs that only require you to take x amount of pictures of certain things, such as: snipers, citizens, drone launchers, resistance members, doormen, recruitement booths, seekers, armored cars, stashes, heavy troopers, generators...so on, so forth, there are many.
If you are going for the jobs as well as just doing the bare minimum you can get alot of them with just the camera. For others you would need the following (may miss some here...) Just so you know what you would NEED to purchase to fulfill other job requirements.
Assault rifle for a basic soldier job.
LMG (I recommend for regular use anyway) for a heavy soldier job.
Crossbow, to get the flamethrower, any soldier kill I believe.
Shotgun for shocktrooper kills(they're the tan uniform with the black helmet)
Inferno launcher on the shotgun, any soldier I believe.
Battle rifle, to get the Marksmen Rifle, for a sniper soldier job.
Freedom Launcher any soldiers.
RPG Heavy soldiers.
Proximity explosive, for a armored car destruction job.
I think there is a kills with a hacked Wolverine, and with hacked seekers.
There are also 2 more I can think of with the knife, which is given so no money need spent. Melee seeker drones, and takedowns on any KPS soldier.
You don't need all these to hit 20, but the knife ones are pretty easy, and the LMG are pretty easy on deathwish. A hack and a proximity on armored cars would be as well. Marksmen, probably, didn't try it as already had the achievement. Flamethrower and inferno launcher I killed myself on accident more then the enemy lol. The hacked wolverine and seekers (if that is a thing, really can't remember)
Just a note for gathering money for weapons, attachments, and gear ( as you might want to fully loadout on gear to help beat the game ) look for white containers (like the containers with motorcycle stashes) many of these have locks on them you can cut. In these containers are 10-16 monitors/computers/hard drives. Easy money makers without risking combat. They can be just on the ground or attached to a semi truck.
Happy hunting