Experimenting with f-stops

When using a macro lens it is vital to have an understanding of f-stops.  If I left my camera on the automatic setting it would always pick f/2.8 or f/5.0 when I'm taking macro images.  The f-stop will determine the aperture.  The aperture determines how much light enters the sensor on the camera.  The smaller the f-stop number the larger the aperture so the more light hits the sensor.  Alternatively the larger the f-stop the less light will enter the camera.  With larger f-stops the shutter speed is slower so a tripod may be necessary, increased noise may also arise leaving images looking grainy.

For the following images of an asiatic lily, I had the camera on the AV setting.  I fixed the ISO to 200 and changed the f-stop.  The camera determined exposure automatically.

Here I used f/2.8, exposure 1/1000s, ISO 200

F/2.8 gives a minimal depth of field which results in the stigma being the only part which is in focus.

f/5.0, exposure 1/400s, ISO 200

Slightly more detail is starting to reveal.

f/13.0, exposure 1/50s, ISO 200

Now you can see the spots on the petals and more detail in the anthers.

f/25.0, exposure 1/13s, ISO 200

A larger depth of field is given showing the most detail.