Sharpness

15. January 2009 by Dave Mo.

This is a very basic introduction to achieving tack-sharp photos.

 The main thing to control sharpness is shutter speed. The faster the shutter opens and closes, the less time something has to register on the film (digital sensor) and move across it (blur). Given that, to have the sharpest photos, you would set your camera for as fast of a shutter speed as it has, right? Wrong!

As with everything else in this world, there is a trade-off. When you have a super fast shutter speed, light has a very short time to get to the film (sensor). This has a tendancy to lower your overall exposure. Try this, if your camera has a manual mode, turn it on, set the shutter speed as fast as it will go, and take pictures. Now, this may not work with shutter priority mode (Tv or S on some cameras), as the camera trys to balence everything out.

So now you have very dark photos. What do you do? Well, you make other adjustments. If you need a very fast shutter speed, you can increase the ISO, which, in a nutshell, makes the camera more sensitive to light, or, you can open up the aperture. Be aware that higher ISO’s may increase noise and grain, and large apertures have limited DOF (depth of acceptable sharpness).

Last thing, handholding. When you handhold a camera, depending on how well balanced you are, you may need to use a very fast shutter speed. The general rule-of-thumb is to use a shutter speed that is the reciprocal of the focal length of your lens. This means that with a 30mm lens, you would have a shutter speed no greater than 1/30 sec. Now, that is in 35mm terms, if you have a digital SLR or point-and-shoot, this changes. For example, Olympus cameras have what is called a 2x crop factor. This means that the same 30mm lens on an Olympus digital SLR would have an effective focal length of 60mm (2×30), and you would need a shutter speed of 1/60 sec. Why is this important? Because, the rule-of-thumb is from the 35mm days. It works, you just have to be careful. Other camera manufactures are different, APS-C sensors (Canon) have a 1.5x crop, Nikons have a 1.6x crop. Just refer to your cameras documentation.

 Well, thats it for now. I hope everyone can get something from this, and I will post again soon.

Dave

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