Sharpness

Sharpness:

Myth: To get sharpness in your landscape images keep aperture at f/8 minimum.Myth Buster: Some experts even recommend very very small apertures, to the effect of f/22. Actually what happens is that Depth of Field increases at smaller apertures and thus gives a feel of better sharpness. To get better DOF at wider apertures read about "Hyperfocal Distance" below

But there are some issues with doing the above. Firstly, If you have sensor dust, it will show when you go beyond f/8 or f/11. Whats the solution? Keep touching up the photos post clicking or get your sensor dust cleaned.

Secondly, at very small apertures diffraction occurs, which means rather than sharpness increasing, the picture actually gets softer. To know more about this read http://www.kenrockwell.com/tech/diffraction.htm

The aperture I love personally is f/8. This works for most lenses. My Sigma 105mm f/2.8, 1:1 Macro rocks at this aperture. Depending on the widest aperture a lens has, the sweet spot of a lens is around the f/5.6 to f/8 mark in general.

To Improve DOF focus on the Hyperfocal Distance-http://www.dofmaster.com/hyperfocal.html, instead of focusing at the nearest object or at infinity

How to get sharper images?

1) Use a Tripod as often as possible. This avoids any camera shake due to lower shutter speeds. SLR cameras have a "mirror lock up" function which avoids shake due to jarring of the mirror. Use a remote to click instead of the click button on the camera to further avoid shake. Rule of thumb for hand held shots-do not decrease shutter speed below the reciprocal of the focal length. For example do not reduce shutter speed below 1/200 for a 200 mm lens. At least use a monopod or support, it really helps

2) If you have the budget you could also buy lenses with Image Stabilizers (Canon) or Vibration Reduction (Nikon) or any other lens which has this functionality to avoid shake, they are worth it. Instead of forcing customers to upgrade lenses with Is these companies could come up with cameras with IS but then how would they make money?

3) Manual Focus: Sounds counter intuitive? Its true, most of the time manual focus will give you better results than auto focus, especially if you are working out of a tripod. I accidentally discovered this when the auto focus feature of my Sigma 105mm f/2.8, 1:1 Macro stopped working. I was forced to focus manually and suddenly discovered what my lens was capable of at f/8, be it portraits or Macro. most of my portraits are with this lens. If you are a beginner, I would suggest that you take your photos both in auto and in manual mode where ever possible till the time you master the art of manual focus. Cameras autofocus can get fooled and some lenses (for SLRs) have some calibration issues with the camera body

Try the above and you will find the sharpness of your images a notch above the results you have been getting. Good Luck!