I just thought I’d take a little time to write about how to use digital cameras of today. Most are the same in their features so I will try to speak in generic forms for use on any digital camera.
First….DO NOT use automatic until you have learned what the cameras brains are doing. The automatic feature is generally good at making a lot of decisions that you should be making. For example, what white balance are you shooting in? If you are using flash, then set the presets for flash on the white balance. If something else pops up like and strong house light which is incandesce then you would adjust the white balance for that. Most of the time the white balance for a given area and time stay pretty constant therefore, you should just leave it set for the area you are working.
Second, Have the right lens for the job on the camera. If you use digital zoom you are wasting the pixels in the finished image. You could be making a 30 mega pixel camera into a 5 megapixel camera by using only a portion of the image. Cropping the image in the camera is essential to good photography in the digital age. If your camera has interchangeable lens, you should change lens very few times unless you are in a very clean environment. A windy day on the beach is no where to be changing lens.
Third, knowing the exposure before the on board computer (automatic) does the job. Why? Because the exposure system is based on the 18% gray card for exposure. What is that? If you took a 18% gray color on a piece of paper and metered off of it you’d get a perfect exposure. If your camera reads off an object that is pure black, it will try to expose it to a 18% gray color and thus overexposing the image. That’s why if you take a picture of a black car it comes out too light and washed out. Same is true for a white object (snow scene), it will try to make the image too dark as it tries to make the white a 18% shade of gray.
There is a easy way to have exposure for outdoors at the tip of your tongue. It’s called the “sunny rule of 16”. I first learned this from my grandfather who was also a professional photographer (1917-1970). Here is the rule: Your exposure is 1/ISO for the shutter speed and the f-stop is f16 on a clear sky sunny day and if the object you are photographing is lit directly by the sun. If your object is under a tree in an open area around it (light Shade), drop 2 f-stops and you should be good to go.(1/ISO @ f8). If you are in closed shade, this is where you shade is pretty dark, you would drop another f-stop to f5.6. Another way is to use that histograph on the camera. It’s that math class graph that is white on a black background. It gives your 256 shades of gray values in any image. The left is the darker values and the right, the lighter values. It is the quantity of shades of gray on the pixels in the image. The more you have the bigger the bumps in the graph. What is important is the ends of the graph. There should be a very small quantity of pure black (last value on left of graph) and very small or no quantity of white on the right side of the graph. To move the exposure to lighten it, you move the exposure values (f-stop (lower) and shutter speed(lower #’s) or ISO(higher #’s)) to move it left until it has the above mentioned values on left and right of graph. If you took an image of 2 shades of gray objects in a image, your graph would be 2 or 1 bump somewhere on the graph from left to right. What is important is that the very small line at the bottom goes all the way to the left and right, not how big the bump is in the middle.
Now comes the part of how f-stop and shutter speed work together. f-stop is for control of the “depth of field” or in other words, the place where your lens is in sharp focus from the front to the back of the image. The higher the f-stop, the greater your depth of field. The shutter speed is used for control of movement of the object you are photographing or if your camera is moving. The faster the shutter speed, the more stopping power you have to a moving object or camera. For example, if you are photographing a person walking and you want to stop most all movement or blur in the image, you would use a shutter speed faster than 1/125 of a second.
And now the tricky part, if you raise the shutter speed you need to lower the f-stop to get the same exposure by the same value. If you were using 1/125 at f5.6 and wanted to get a greater depth of field to make more “stuff” sharper through the image, you could use 1/60 at f8. Most hand held images need at least 1/60 of a second shutter speed to prevent camera shake/blur for happening. If you get very experienced like a trained sharp shooter in the Olympics, you might be able to pull off shots at on a 1/15 of a second. There is some new technology out there in digital cameras to help stop this by vibration control (VR) lens that counter your body movement with gyros and such. You can also cheat on the above numbers by using IOS settings. If you use lower numbers on the ISO, you get less “noise” or grain in the image. If you use higher ISO’s, you can generally go up to ISO100 on today’s prosumer cameras and as much as ISO5000 for really good cameras. This is a very good feature of digital cameras today. Back in the day, we had to change the roll of film to a higher ISO (ASA) back then. The fast films were only ISO800 or you could push process the images in development but would be very grainy images.
Lastly, Get a GOOD camera to start off with. Pay the price for something you can grow into to and be using for a career in photography even if you don’t think you’d ever want the job of a professional photographer. Good is good to have when you are capturing that once in a lifetime achievement.