Another View brings up an important point that I didn't mention. Set your meter to spot or at least center weighted and if you can adjust how much is center weighted bring that levle down. I like to think from extremes and work from there. If you come upon a scene where there is no movement what so ever, set your camera on a tripod, choose an ISO that will not show alot of noise(digital) or grain(film) (unless you want it) and choose an aperture that will show the image as you want it. The camera will choose a long shutter speed which you should note. Everything is in balance and hopefully properly exposed. Now change something or move to manual. If you close the aperture one stop than you will have to slow the shutter one stop or go up one stop on the ISO or 1/2 stop on both. Looking for where to initially set the shutter speed? Put the camera in Program mode to see where the camera wants to go. Knowing that it may not be fast enough to avoid any small amount of movement from blurring. But if you speed it up you will have to open the aperture that amount or speed up the ISO. It's just a balancing act but instead of 2 sides there are 3. Plus you have to have a preconceived notion of how you want the image to come out then back it into those parameters. Like Another View writes reciprocity failure occurs on very long exposures and it is different for each type and brand of film used so don't worry about. Bracket your photos, pros do this all the time, especially if you shoot positive exposure (slide). If you're shooting digital or negative just bracket larger at least a stop. That is why on any pro camera it is very easy to turn on the bracket function. It is usually a button on the top of the body, No menus to search through to turn it on or off. I know you are rock steady and never flinch, we all are, but use a tripod if you can.