While many lenses have a maximum aperture of f/22, some lenses have apertures that go to f/40 or higher!
Generally, photographers do not use any aperture above f/18 or f/22 because of diffraction. Diffraction is a phenomenon which causes a loss in sharpness because light rays are bent around the aperture.
The following is a story of when I broke all the rules and used f/40 anyway!
I was shooting a beautiful Christian cross on a ridge one morning. I knew the sun was about to rise just above the cross, so I wanted to take a picture of the cross silhouetted in front of the rising sun. If that’s not symbolism, I don’t know what is.
The trouble was that I had no neutral density filter, which would have allowed me to block out enough light. Shooting with a telephoto lens straight into the sun is a recipe for a disastrously over-exposed image. I guess I was feeling adventurous that morning, because I decided to use the aperture to block out the light. I had a little grin on my face when I cranked up the aperture right past f/22 and kept spinning and spinning. I was delighted to learn that the lens I was using could be shot at f/40!
I shot at f/40, a shutter speed of 1/4000th of a second, and ISO 100. In almost every case, this would produce a black picture, but I knew it was going to be really bright, so I gave it a shot. The image featured on this page is the shot that those settings produced. No, I didn’t convert the photo to black and white. This is almost exactly as the shot appeared straight out of the camera.
If you’re new to photography, you might want to check out my book, Improve Your Photography. For just $5.99, you can download a PDF of the book that can be read on any computer. Click here to check it out!