I sometimes get questions such as “My photo doesn’t look sharp.  How can I fix it?”

Let’s look at reasons first.  Your photo may be out of focus, but that’s rare with the usual automatic focussing.  Camera shake is another possibility, but that’s easily recognized.  The principal reason for softish looking photos is elsewhere.  For the most part, the problem occurs with pictures taken with a smartphone.  The smartphone lens is designed for a wide angle photo, and it looks like that’s easily taken care of by the “zoom” adjustment. That’s the root of the problem.

The zoom is a fake.  It merely crops the photo to the indicated size.  Therefore, you reduce the number of pixels constituting your. Photo.    Suppose you have a 12 mp (million pixels) smartphone and you crop to 1/5 of the picture.  Then you have only 1/25 of the picture area, so the resulting photo has only 0.48 mp.  Your sharpness depends on your dpi (dots per inch), which relates to the picture area by the following formula dpi = square root of {pixels/(picture area)}.  For a snapshot sized 4×6 print your dpi is therefore only  about 147 dpi, which doesn’t produce a sharp photo.

Given that situation, what can you do about it?  The answer is, not much.  There are some apps that claim to miraculously transform your picture into a sharp one, but their effect is limited.  The fundamental problem is that insufficient information remained in the photo, and there “ain’t no free lunch.”

By Fred Beutler