New answers tagged focus
Touch focus just uses your touch to choose the area of contrast on which to base focus. The auto mode just decides that for itself. There's nothing physically different with the actual focus process.
You'll need to calibrate the positioning of your focusing screen. Usually, there are small rectangular shims which get the screen into exactly the right position. You may need to adjust these. Depending on where you bought the screen, it may have come with some. (Some cameras include shims to position the factory-installed screen, but some don't; I'm not ...
From an optical testing standpoint the main aberration that shows up on axis is spherical - and it varies only due to (F/#)^4, which explains why you are getting a soft focus at a larger aperture. If you look at the top and bottom the the image you see triangles aren't imaged the same, which would probably be astigmatism. I could tell you more if I saw more ...
Hyperfocal distance applies regardless of manual or automatic focusing. The hyperfocal distance is simply the distance at which (when focused on) everything beyond it is in focus. This is a set point for a given focal length, aperture and cone of confusion. It does not change regardless of if you focus manually or automatically.
Yes. The feature in the image that is focused on os the most in-focus distance, with some depth on either side being acceptably sharp. Having the touch-here focus is no different than using an old fashioned split prism: it focuses. Choose a feature to focus on that is in the middle of the intended depth. If you want to be sure, use the eyepiece (not the ...
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