However, I did not create a wide depth of field in this picture. Would there have been a difference in the picture had I narrowed the aperture? Unfortunately, the camera I use can only narrow to f/11.
I wouldn’t worry too much about it, as far as I can see, you’ve done pretty well at getting an acceptable DOF! Remember that you have a different camera/sensor size than all the “big” guys with DSLRs. A smaller sensor will give you more DOF than a large one, even at lower aperture numbers.
Just for fun, I consulted a DOF calculator from Cambridge in Colour. I put in your specs and settings, (Select “Digital Compact with 1/1.8″ sensor” for the “Camera Type”) and it shows that the DOF is infinite for that focal length and aperture value. So the answer is no, stopping down (narrowing the aperture) probably wouldn’t have affected your DOF enough to be worth the bother.
Note that when you start “stopping down” far enough you’re eventually going to get to the point of diminishing returns, where diffraction will create more blurrines than the small aperture sharpens. This is especially significant for smaller sensor cameras because they have such tiny pixels. Think about it, 12 MP on an APS-C size sensor compared to 12MP on a sensor less than a quarter the size! (12MP is 12,000,000 individual pixels.)
You can compare pixel sizes for different cameras at http://www.snapsort.com/compare . For example, here’s a comparison of a Canon DSLR compared to your camera: http://snapsort.com/compare/Canon-T3-vs-Panasonic_Lumix_DMC-FZ30/specs (Scroll down the page till you see “Pixel Size”. As you can see there, the pixel size for the Canon is more than 5x larger than your camera!
Cambridge In Colour also has a calculator for calculating approximate diffraction limits for different cameras. If you set it to your camera’s sensor size, (“Digital Compact with 1/1.8″ sensor“), you can see that f/5.6 is the diffraction limited aperture for your camera.
If you are taking James’s Online Training, you’ll learn more about how snapsort can help you choose a good camera, and how things like pixel size can affect your photograpy!