Controlling sharpness in a photograph. A quick photography class: The aperture controls sharpness and there are other things that will affect the sharpness of a photograph.
A quick review: I'll start with the lenses. The type of lens you use will affect everything in your photograph but I'll stick with sharpness. I personally like the fixed lenses. I have seen that the images are clearer and sharper than when I photograph with a zoom. Not to put the zoom down: the other day I rented an incredible zoom lens (70-200mm) with an aperture of 2.0 and it was amazing!
Back to fixed lenses. I will take several fixed lenses to photograph portraits of families and babies. I use the fast lens. Fast lenses are lenses with wide apertures such as F1, F1. 4 and F2, F2.8. These lenses will allow my images to be sharp and clear.
Of course there is a detail that may complicate things for those of us who may want very sharp images, for example if we are shooting architectural photographs. I learned about this in a photography class many years ago.
Diffraction: When we photograph with a small aperture, light will scatter and will produce a softness that may look like the photograph is not focused all the way in the back or sometimes showing a soft focus starting in the middle of the image.
What to do? Well, I guess the obvious is not to use a very small aperture! Use the largest aperture that will allow the most sharpness. Many people do not realize that depending on your subject an F11 will give you all the sharpness you need.
Digital Photography has had issues with sharpness ever since the beginning. The issues with tones & exposure were resolved by blending the same photograph with different exposures (HDR photography). Why not do this with sharp images?
I photograph the same image several times. Each photograph will have a different area that is sharp. I blend them in Photoshop. I can control the amount of sharpness that my photograph will have. Diffraction in my photography will not be a concern! I do the same when I want a soft focus in the background. I know I can do this with an open aperture or in Photoshop but sometimes the exposure can get ruined.
What a great photography tip!