Diffraction or DOF?
When shooting ‘macro’, at very small apertures, we get diffraction which causes the image to go soft. On the other hand, if we do not use small apertures, we don’t get enough depth of field. What can be done other than increasing the ISO? S.S Nair, Chennai A very intelligent query. But first, to avoid the possibility of any confusion, let us never use the words ‘small’ or ‘ big’ when referring to apertures. Instead, use the words ‘narrow/ narrower’ or ‘ wide/wider’. Hence, for example, f/11 and f/16 would be ‘narrow’ apertures while f/2.8 would be a ‘ wide’ aperture. Here’s what I would do when faced with the problems you have narrated: I would disregard the possibility of diffraction of light and go ahead and shoot with narrow apertures. In my opinion, it is better to have a slightly diffracted but focussed subject rather than have a out of focus subject that has no diffraction. Another ‘trick’ for higher magnification look, is to shoot at 1:2 ( half-life size) rather than 1:1 ( life size), and then enlarge the image as required. You should see better DOF and better sharpness in your picture.