Have you ever taken a photograph and been really happy with
the results on the LCD? Has that
happiness turned to frustration when you get home and load the image into your
post processing software only to find out that it is slightly out of
focus? I know it certainly has for me on
more than a few occasions. Before we get
into what you can do to sharpen up your images there is one thing you can do
that will help out at the time of capture.
Most cameras have a way that allows you to zoom in on the LCD to check
the focus. Find that feature and use it
to occasionally check your work… especially if it is a really important shot.
There are a few things that you can do to help you get sharper images. The items and techniques will not cure every blurry photo they will certainly help.
I would venture to say that this is the one that gets most people. The longer the shutter is open the greater the chance of a blurry image due to motion. The motion can be from you and camera shake but it can also be from your subject.
There is a guideline regarding shutter speed that will help you get sharper images. Remember, it is a guideline and not a hard and fast rule. The guideline says that when you are hand holding the camera that the shutter speed should be equal to or greater than the millimeter the lens is racked out too. For example: If you have a 300mm lens that you are hand holding and you want sharp images you need to have a shutter speed of 1/300th of a second or faster. Remember, this is a guideline not a rule. It can be broken with some success but for me it works great most of the time.
ISO is basically the sensitivity of the sensor to the light. The higher the ISO the more sensitive the sensor becomes. There is a trade off here though. The higher you go the more noise you introduce into the photography. So, you might be asking “what in the world does this have to do with sharp images”? Don’t worry, that is a valid question. The quick answer: It doesn’t. However, what it does do is it allows you to raise your shutter speed if you are in areas where there isn’t enough light to get the shutter speed to the guideline listed above. Many photographers fear raising the ISO. While that was a huge issue 5 to 10 years ago most modern DSLRs produce great images at ISOs of 800 or 1600. Don’t be afraid to raise that ISO. Besides which would you rather have, a blurry image due to camera shake and/or subject movement or a sharp image with a little bit of noise?
Aperture controls the depth of field (DOF). Depth of Field is the distance between the nearest and farthest objects in a photograph that appear reasonably sharp. While Aperture really doesn’t affect your focus it can have an effect on the sharpness of the image. Specifically at wider apertures when the DOF is shallow. If the aperture is 2.8 or larger (smaller number) the plane of focus can be extremely narrow. It can be so narrow in fact that if you are taking a picture of a person who’s face isn’t parallel to the camera one eye can be in focus and the other out. This can give the illusion of a blurry out of focus image. If you happen to be taking a photo of an individual this can give a good effect. However, if there are multiple people in the image some could be in focus while the others are out of focus.
So, is there a guideline to use here? You bet, but it really only applies for when you are taking photos of groups. The guideline is to set the aperture to approximately the number of people being photographed. If you have 4 people in a group then make sure your aperture is at least f4 or smaller (larger number). Personally, if I am photographing more than one person I will start around 5.6 to make sure that focal plane is large enough to produce crisp images. You can deviate from this but be sure to zoom in on the image to make sure everything you want to be in focus is actually in focus.