Some things that can give you false evidence, at first they may seem genuine but on closer inspection or at been studied by a more observed person things may not be what they seem. The most common things that provide false evidence are photographs but there can be other ways.

Examples of false evidence

On photographs

Camera straps getting in the way of the lens – may be mistaken for things like a vortex

Matrixing 

Hair - leaning over to something to take a photo, your hair goes over the lens or strands of hair may fall in the way when photograph is being taken

Over exposure – when facing lights your camera may make this effect

Double exposure – these can be mistaken for apparitions

Dust on the lens of the camera – they may be seen as orbs amongst other things Photoshop - tampering with the photograph on software to make something seem to be in the picture that was not really there.

Other

EVP – evidence may have been compromised in some way

Personal experiences – reports from someone who have claimed they have witnessed something paranormal.