Equipment every Private Investigator needs
What equipment does a Private Investigator in the UK need?
A good pair of binoculars is required when you need to see quickly into the distance, these aren't an every day item and I use them rarely nowadays however they are needed. Spend some time learning about the sizes and you will need at least x40 zoom on the them to get good usage. Try a brand name like Celestron to ensure good quality.
Most PI's have a DSLR camera for gathering evidence, not all PI's have the right telephoto lens. Grab at least a 350mm telephoto lens for those long distance photographs, not the most discreet bit of kit but the shots you can get are amazing at long distance.
Even when in the vehicle a tripod may be needed for telephoto usage to ensure a stable shot. This is doubly important in low light condition when the shutter speed has be decreased and those shakes can cause more problems. Heavy duty tripods are more often needed for longer range photography, the tripid pictured may not be sturdy or strong enough.
When the going gets tough, you may need a portable flood light. At night in the middle of nowhere trying to set up some kit or locate something. You may well find yourself in need of a good portable light. Rechargeable and handy to have a portable flood light is a bit of kit you'll be sorry you didn't pack.

