Hand Held Cameras, Part 5
Depth of Field
One of the major problems with hand held cameras is that it is difficult to get a good depth of field
This article continues my thoughts about hand-holding cameras for increased shooting flexibility and creativity that have been the subjects of the three previous posts. Go the the first part of the hand-holding series.
I shot the above picture in mid July on day one of my month long summer shoot. I was driving through the San Luis Valley of southern Colorado on my way to our old home in Howard, Colorado. I had my new Canon Rebel with the new Tamaron 18-270 lens on the passenger seat right beside me. It was so easy to stop and take pictures that I was stopping fairly regularly, wandering around a bit in the close vicinity of the car and shooting whatever looked good. In the location of the above picture I shot half a dozen pretty good images.
Since I was handholding the camera, I was shooting at fairly high speeds as I didn't want any movement blur in the images. As a result, the lens apperature was not all that small. This picture was shot at 1/250 at f-8 with the lens zoomed to 35mm. And as a result of that, the picture is not sharp all the way to the distant background, ie it has poor depth of field.
What happened was that I forgot I wasn't shooting my Olympus point and shoot camera that has a small sensor and thus lots of depth of field. (If you really want to know why small sensor cameras have more depth of field than large sensor cameras, here is an article that explains all that technical stuff.)
If I had shot this picture with my Olympus using the 28mm lens zoom and the same aperture of f-8, I would have had tons of depth of field and the picture would have been sharp all the way from the foreground to infinity.
Take a good look at the picture above and you will see that the yellow flowers are sharp but the background is very fuzzy. In this case, the picture doesn't really look all that bad because the important stuff is in focus and it's only the far background that is blurry. This is often OK as the sharpness of the foreground separates it from the blurry background and sometimes this is actually very nice; sometimes I actually try to do this.
Other times, like this time, I really wanted the whole picture to be sharp all the way through and this meant I had to have good depth of field. You get depth of field when you use a very small f-stop like f-22, a wide angle lens like a 18mm or a 28 mm lens, and you are three or four feet away from the close foreground.
In this case, I really intended the whole picture to be sharp all the way to infinity and I blew it. The main problem was that my f-8 aperture was too large. To get good depth of field with a close foreground, using a larger sensor camera like the Rebel, you really have to use f-22.
However, if I had used f-22, then my shutter speed would have dropped to a 1/30 of a second which is generally too slow a speed to handhold the camera without getting motion blur.
What to do? How do you handhold the camera, get good depth of field and sharpness, and avoid motion blur?
There are several things you can do. One of the best is to use a higher ISO speed. In the old days this meant changing film to a higher speed film. However on a digital camera you just set the camera ISO at a higher speed. When handholding the Rebel, I quickly began shooting, not at the default speed of 100, but at ISO 400 or even 800.
Shooting at ISO 800 would have allowed me to shoot the picture at f-22 and still keep the exposure speed at 1/250 of a second. This would have given me a good depth of field and keep the whole picture in sharp focus with no motion blur.
Go to the sixth part of the hand held camera series.