Lens Problem No. 5: Lens Diffraction
If you’re using good technique and your images are still losing important detail, it may be due to lens diffraction. It’s caused by using a very small aperture to gain a greater depth of field, and results in a slight softening of the image.
Pretty simple this – where possible, avoid using your lens’s smallest aperture (such as f/22 or f/29 – find out when you should use a wide or small aperture).
Many landscape pros set an aperture of f/16 by default for precisely this reason (learn more landscape photography secrets the every pro still uses).
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