Project Focus. Exercise 3: Focus at different apertures

Working indoors again, I have decided to photograph, a favourite object of mine in the house, an ornament that was purchased when I first arrived here in Oman 3 years ago and was setting up home in the Middle East. 
I have placed the figure on a glass table, and placed a glass vase holding flower behind the figure, this is also on the table.  
I am hoping that the placement of the flower and vase will show the limits of sharpness in each photograph, DOF. when changing the aperture. 
I have framed each photograph identically as can be seen.

• Canon EOS 400D
• ISO 100 in each photograph
• No flash
• Aperture Priority
• Tripod 

fig 1                                f/4.5

Widest aperture

The largest aperture isolates the subject, here the subject is in sharp focus and the background has been rendered out of focus.  In this case shallow depth of field has caused flower in background to be out of focus.  Edge of glass table completely out of focus too.

fig 2                                  f/8.0

  fig 3                               f/16.0

Mid-point of aperture scale

Here I find that much of the photograph is out of focus, an all over softer image.  The edge of the glass table 

just visible.

fig 4                           f/22.0

fig 5                           f/32.0

Smallest aperture 

Using a smallest aperture here (large value) extends the depth of field from the foreground all the way to the background.  

Very clear definition of edge of table and visually it is possible to see glass vase at rear of figurine.

e

My thoughts on this exercise

I have come to understand a little more about aperture being expressed as F-stops. Still have much to learn though.  I see there are calculations on the internet that can be used to determine focal length, these I need to study at a later date.  

Learning points:

• large apertures where lots of light gets through are given smallest f/stop numbers
• Smaller apertures where little light gets through have largest f/stop numbers

therefore f/4.5 is a much larger aperture than f/22

and

• depth of field is distance where objects are in focus.