When the lens gets close to a subject (i.e. flower etc. ) depth-of-field gets short and a small aperture (f20+) should be used. Shooting with an aperture in the 20’s (wish you still were?) extends the shutter speed time. Know how long you can hold the camera/lens without blurring the image. Speeds that are longer than your max will require some form of camera support. Tripods are the first thought, but anything will work. Why switch to decaf?