There are several factors that influence how sharp your images are taken with a DSLR camera. While shutter speed and aperture settings are the most significant, how close you are to your subject and what lens you choose can also affect a photo's quality. Settings can vary from one camera to another and under different lighting conditions, so it's a important to go out and experiment with a new camera and then experiment again if you purchase a new lens. Take several photos of the same subject while changing your settings. You can then compare what works best with your camera in different circumstances.
Shutter speed greatly affects how sharp your images are, especially when there is fast action in front of the lens. Between the moment the shutter opens and the moment it closes, all sorts of things can happen. For example, a shutter speed of 1/60 may seem fast, but if someone is jogging past at 5 miles per hour, she has moved almost an inch and a half in that 1/60th of a second. For fast action, use the highest shutter speed possible. For most pictures a shutter speed 1/250 or higher should work.
Low aperture settings allow the maximum amount of light into the camera. Using a higher aperture setting, which lets in less light, is known as stopping down the lens. There are two reasons to stop down the lens. First the subject you focus on will be sharper. Using a low aperture setting of f/2.8 will result in less detail, less subtlety in color differences, than using a higher setting of f/8. Secondly, the details in front of and behind your focus will be sharper due to the increased depth of field.
Depth of Field
A lower aperture setting decreases the depth of field in your photo, meaning anything slightly behind or slightly in front of your focus will be blurry. A higher aperture setting increases the distance of this depth, resulting in crisper images. A close focusing distance also reduces the depth of field. For example, if you stand close to a subject with a wide-angle lens and focus on the tip of the nose, the eyes can be blurry, whereas if you stand back with a 200mm lens, the entire face will be in focus.
The ISO setting on a DSLR camera determines how sensitive the camera is to light. A high setting is important in low-light conditions, but for sharper images in good light, use the lowest setting possible. This is usually 80 or 100 on most cameras. In low-light conditions when a high ISO is needed and a faster shutter speed, use a tripod to reduce noise from the vibrations of your hands. Finally, don't forget that the lenses themselves add noise, especially if the lens is dusty, or even if the lens is of poor quality. The price difference between a cheap lens and a good lens can be significant, but if you need sharp images, quality lenses are well worth the investment.
Even the sharpest, most detailed image can be completely destroyed if you use the wrong settings when exporting it from the camera. Converting an image to a JPG with a small file size can destroy the fine details in any image. For best results, transfer the images to your computer in RAW format and use a photo-editing tool like Photoshop or GIMP to process them. These programs include handy sharpening tools to bring out the details in blurry or fuzzy areas on an otherwise perfect photo.
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