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. Â 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. Â 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. Â 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. Â Shooting with a telephoto lens straight into the sun is a recipe for a disastrously over-exposed image. Â I guess I was feeling adventurous that morning, because I decided to use the aperture to block out the light. Â I had a little grin on my face when I cranked up the aperture right past f/22 and kept spinning and spinning. Â 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. Â 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. Â The image featured on this page is the shot that those settings produced. Â No, I didn't convert the photo to black and white. Â 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. Â For just $5.99, you can download a PDF of the book that can be read on any computer. Â Click here to check it out!
Nice experience, please may I have again your meetup link, to keep when you will have another semimar or workshop, thanks