There is an old adage about what the slowest speed one can hand hold steadily. It goes: the slowest speed is one that approximates the focal length of your lens in millimeters. In other words, most 4 x 5 graphics have a 135 mm lens. That would mean you can hand hold comfortably at a shutter speed of 1/125 of a second or faster. A 150 mm should be OK at that speed too with care. For 35 mm cameras, a 50 mm lens can be hand held at 1/60. I tell my students that with practice they should be able to drop down at least another speed.