Focus question and advice please!

Started 2 months ago | Questions thread
JimKasson
JimKasson Forum Pro • Posts: 24,949
Re: Jim's plot a bit annotated...

Erik Kaffehr wrote:

Notes:

  • Distance scale is logarithmic. Left side = 1m, right side = 1000m focus point 30 m
  • Diffraction is shown as red circle and defocus (CoC) is shown as green circle corresponding images added. These calculations are approximate and use 4.8 microns.
  • The grid shown is the pixel spacing.

Jim's plots show some interesting things. One is that stopping down can handle background well. Jim focused at 30 m and that is near hyperfocal distance for CoC = 0.010 mm and f/16. The diffusion spot will be around 0.012 mm from focus point. Stopping down further will not help background sharpness.

The parts near the camera, that is a few meters, can never be really sharp.

Good explanation, Erik.

-- hide signature --

Posted as a regular forum member.
https://blog.kasson.com

 JimKasson's gear list:JimKasson's gear list
Nikon D5 Fujifilm GFX 50S Sony a9 Sony a7R III Sony a7 III +5 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow