You can create many distinct and exciting effects by just experimenting with various ƒ-stops of your lens. One of the most popular effects known among landscape photographers is the sunburst effect, which is also known by other names, such as Sun Star, Sun Flares, etc.
Sunburst effect gives star lines spike around the sun, which can add more visual interest to the sky, especially just a few moments after sunrise or before sunset. The technique to get a sunburst effect is simple; you need to set your lens to higher ƒ-stop number (somewhere between ƒ/11 or ƒ/16). I set my ƒ-stop to ƒ/14 for the above composition, which is moderate enough to get a good sunburst effect.
Note that higher the ƒ-stop, lowers the quality of your photos. You have to constraint yourself while picking the higher number for your composition. Anything between ƒ/11 and ƒ/16 is good enough for the best result. Higher then that will degrade the quality of the photo because of the diffraction caused by high ƒ-stop.
The number of star spikes will depend upon the number of blades you have in your lens. Double of the number of blades you have in your lens and that’s the number of star spikes you will get in your composition. For example, if your lens has seven blades, you will get 14 spikes.
To get more distinct star spikes, try to achieve narrowest possible sun source. That’s why this effect is more effective when the sun is just rising on the horizon. Alternatively, try hiding the sun behind a tree branch or rock, on something by changing your camera position or your composition.
A vital thing to remember when working with the higher ƒ-stop numbers: make sure your lens front element is spot clean from any dirt or smudge. Any imperfection on the front glass of your lens will grossly expose as huge circular spots in your photos. Don’t be surprised if a minuscule dust spike on your glass you never noticed on other pictures is enlarged and spotlighted in your sunburst photos. So do regularly visually glance over and spot clean the front element of your lens; removing those circular spots in Photoshop is not fun.