It sounds like iCloud photo library is not for you because the point is that all of your photos will be on all of your devices.
If you turn iCloud photo library off but use photostream, that would put all new photos from any device on your mac and in iCloud, but also on every other device that has photostream turned on.
If you ONLY want each device to have the photos taken with that device, then A) don't use icloud photo library, and B) turn off photostream. You can still have the device back up to iCloud, and that backup will include the camera roll. BUT, you would have to manually transfer new photos to your mac through iPhoto.
One final suggestion: on an iOS device, if you ARE using iCloud photo library, there is an option in Settings --> Photos --> "Optimize iPhone (or iPad) Storage." If you click that, rather than "Download and Keep Originals," then that device will only keep device-optimized versions of photos rather than full resolution photos, which can save a lot of space.
