Exercise: Focus at different apertures

Again it took me a few attempts to get the right subject matter for this exercise. I tried with gravestones in the local churchyard

But couldn’t understand why the shot taken with the smallest aperture (f20) seemed no sharper than photos taken at wider apertures. Then I noticed that I had taken the photo hand held but, because of the narrow aperture the shutter speed was 1/20 second. LEARNING POINT always check shutter speed you are using with hand held shots and always take your tripod with you!!

So I decided to try the technique with a pile of logs

I certainly had to use my tripod this time as the logs were indoors and the exposure time for the smallest aperture was 6 seconds. Although the photos did show the effects of different apertures on how sharp the photos were it still wasn’t easy to see which areas were sharply in focus and which weren’t. I wanted to find a subject that showed very clearly the areas that were in sharp focus when different apertures were used.

I remembered  seeing a photo in a book where pasta had been used to make an abstract pattern, so I decided to try this.

I put some pasta shells on the table near the back windows and used my macro lensto take the photos. The results were quite good clearly showing that smaller apertures gave larger areas of sharp focus. But I still wanted to show this as clearly as I could so I replaced the pasta shells with spaghetti laid horizontally. Looking through the camera viewfinder this looked OK but I wanted to make it a bit more interesting, so I laid a couple of strands of spaghetti diagonally as I had read in ‘The Photograper’s Eye’ that diagonal lines were more dynamic.

That is how I arrived at the results below and I think the edited photos that have blacked out the areas not in sharp focus clearly show the effect that aperture has on this.

The first photo was taken with an aperture of f3.8 – the area in sharp focus is shown on the right:

The second photo was taken with an aperture of f16, again the photo on the right illustrates the area in sharp focus.

Finally, the third photo was taken with an aperture of f36 (5 seconds exposure) and shows the much larger area in focus when using the smallest aperture on the camera.

Leave a Reply

Your email address will not be published.