I enjoy taking photographs of flowers. Sometimes I like to have the entire flower in focus and sometimes I like to have only a portion of the flower in focus. These are two shots of the same flower, same place, same time. One I shot at f/4.0 for a shallow depth of field and the other at f/40 for a greater depth of field.
You can see that the background is completely blurred out in the photo shot at f/4.0 and all of the petals around the center are “soft” and a little blurred.
The background in the photo shot at f/40 has more detail and all of the petals of the flower are sharp.
Maralee
P.S. As a side note, if you have dust on your sensor, it is going to be much more pronounced on the photos if you use a greater depth of field than if you use a shallower depth of field.
Through My Lens 
Gorgeous dahlia photos!
Thanks Cee. They are beautiful flowers. I didn’t know what they were for a long time but now they’re one of my favorite flowers.
I did purple flowers, too, so great minds on the same photo track and all that. 🙂
janet
For some reason I’m always drawn to purple, and the purple/yellow combination. Thank you for directing me to your blog.
I love purple and yellow pansies each spring. They’re so vibrant and joyful. Thanks for visiting my blog. I enjoy meeting people through the Photo Challenges!
janet
Thanks for explaining. Were you using a macro lens? What was your focal length or distance?
For these photos, I used my 90mm macro lens. I was probably about 3-4 inches from the flower.
I just love the color. My favourite is the first one. 🙂
Thank you, Inga. Purple is my favorite color.
Sooooo gorgeous. I love dahlias.
Thank you very much. Dahlias have become one of my favorite flowers.
I always find it so amazing how something as simple as a change in DOF can take the same subject, same composition, and result in two entirely different photographs. There is such a different mood or feeling to both of these equally beautiful photos.