Sony RX10 M3: Diffraction Samples

On this page, I present Sony RX10 M3 photos taken under similar conditions but with varying aperture to demonstrate how fuzziness caused by diffraction sets in at smaller apertures.

Note: See also page Calculating the Optimum Aperture for Different Sensor Sizes (Diffraction Limit) for a general discussion of diffraction.

Introduction: Diffraction as a Limit to Stopping Down Lenses

As you stop down, "diffraction" sets in and reduces image sharpness. The more you stop down, the larger diffraction effects get. Diffraction can be described as "the spreading out of a light beam when it's 'squeezed' though a small aperture." The smaller the aperture, the more the light spreads out.

This works differently for different sensor sizes, and you can read more about this on page Calculating the Optimum Aperture for Different Sensor Sizes (Diffraction Limit). All in all, the generalized results for the "optimum apertures" are:

• f/4: small sensor cameras (1/2.3", 1/1.7")
• f/8: 1" sensor cameras
• f/11: MFT and 4/3" cameras
• f/16: APS-C cameras
• f/22: full-format cameras

Please note that this are limits that diffraction sets to image quality; it sets in at much smaller f-numbers, but this is a "gradual" process (for details, see page Calculating the Optimum Aperture for Different Sensor Sizes (Diffraction Limit). Also note that these limits, may be a "matter of taste". Some authors maintain that diffraction sets in for 1" cameras already beyond f/5.6.

Sample Photos

In the following, I present sections from example photos that I took at different f-numbers (up to f/16, the smallest aperture on the camera) and with the Sony RX10 M3 to look for diffraction effects. Of course, this is just a "quick-and-dirty" investigation. Nonetheless, diffraction effects can be found on the computer screen at least at 100% magnification. What this means in your photographing practice, is up to you...

 Using the following photos taken with the Sony RX10 M3, you can observe on a computer screen at 100% magnification how diffraction increases with f-number. About the photos: The photos were taken with a tripod at the f-numbers f/4, f/5.6, f/8, f/11, and f/16 in A mode. Distance was set using AF at a distant target. ISO was set to ISO 200, and a focal length of 35 mm (equiv.) was used. The images below are 100% sections. Click the images to download or view the photos in full size. Overview sample f/4 f/5.6 f/8 f/11 f/16 (maximum f-number) f/4 (different photo, for comparison)

Sample Photos - Close-up

In the following, I present sections from example photos that I took at different f-numbers (up to f/16, the smallest aperture on the camera) and with the Sony RX10 M3 to look for diffraction effects with a close-up motif. Of course, this is also just a "quick-and-dirty" investigation. Nonetheless, it shows that close-ups are not useful for such tests because the depth of field is limited and thus, interferes with what you want to investigate...

Using the following photos taken with the Sony RX10 M3, you can observe on a computer screen at 100% magnification how diffraction increases with f-number.

 f/5.6 - original processed, original The photos were taken hand-held at the f-numbers f/4, f/5.6, f/8, f/11, and f/16 in A mode. ISO was set to ISO 200. The images are 100% sections. Click the links to download or view the photos in full size. f/11 - original processed, original f/16 - original processed, original

Selected Sections

Click the images to view the sections in double size (100%) in a new window or tab.

 f/4 f/4 f/5.6 f/5.6 f/8 f/8 f/11 f/11 f/16 (maximum f-number) f/16 (maximum f-number)

Conclusions

My basic conclusion from this test is that I will not use an aperture value of higher than f/8 on the Sony RX10 M3. The deterioration at f/11 is visible, and much more so at f/16 when I view the test photos in full size on the computer screen.

References

 gerd (at) waloszek (dot) de About me made by on a mac!
 20.01.2019