File Size as an Accurate Proxy for Image Detail
Related: Eastern Sierra, external articles by Lloyd, peak bagging, Zeiss, Zeiss DSLR Lenses, Zeiss Milvus, Zeiss Milvus 100mm f/2M
Get Zeiss Milvus 100mm f/2 at B&H Photo.
Compressed file sizes are an accurate proxy for total image detail, because more detail means less compressibility, and less detail means the image is more easily compressed.
Detail is the sum of many factors, but the key ones are depth of field, micro contrast, losses in sharpness and micro contrast from diffraction, sharpening level, and noise from the sensor/camera. See also:
- Depth of Field Challenges: Bypass the Limits with Focus Stacking, Near or Far, Macro or Landscape
- Micro Contrast and the Zeiss 'Pop'
- All articles for Zeiss Lenspire
Below, using file sizes from this aperture series, it is clear that f/6.3 is the best aperture for the scene, with f/4 and f/9 close runners-up. Apertures f/16 and f/22 are disasters, far inferior even to f/2.
These differences would be greater if there were more landscape and less blue sky, since blue sky contains little detail. Smaller apertures down to f/13 would fare better if there were a lot of out of focus detail to start.
Focus stacking vs single frame detail
Focus stacking provides a huge increase in detail. Using file size asa proxy for total image detail, we can see that versus the most optimal f/11 frame, the focus stacked image delivers a 67% greater amount of image detail.
Going to f/2.5, the detail more than doubles. And that is versus the f/2.5 frame that is placed so as to sharpen the majority of the image. Obviously an image shot entirely at infinity focus on an infinity scene will have little to gain; conversely an image with a tiny in-focus area could have gains of 10X.
