Essential tremor, benign tremor, benign essential tremor, familial tremor.... One of those little things associated with aging - although some get it pretty young and some get it pretty bad, involving the head shaking as well as the hands. Essential tremor falls into the category of an "intention tremor" - meaning that your hands shake when you use them, but not generally while at rest. It is also a high-frequency tremor. A slower frequency tremor of the hand while at rest may be associated with Parkinson's Disease. But in medicine there are always exceptions.

Higher shutter speed and using a tripod with a cable release are helpful for the photographer with essential tremor. As Jerry says, medications can help - most often the beta-blockers like propranolol can be helpful. They can cause drowsiness, a slow heart rate, and low blood pressure (they are used to treat high blood pressure and rapid heart rate as well). There are long-acting forms, but sometimes i like to have patients try the shorter-acting forms that I advise only taking if needed - if you are just sitting at home you may not need to take it, but if you are going out to eat or do some photography, it might be helpful. Another helpful medication is a low dose of diazepam (Valium). It may have fewer side effects than a beta-blocker, which also should not be used (or used very cautiously) in patients with asthma or insulin-dependent diabetes.

For severe tremor not easily treated with medication, there is a newer therapy called MRI-directed brain ultrasound offered in advanced neurology centers that can actually be curative.