S23 Ultra Manual Focus Study - Expert Raw Mode W1 Camera
The S23 Ultra in Pro and Expert Raw modes has a manual focus adjustment. This adjustment is
very important particularly for astrophotography where pinpoint sharp star images are desired and
the infinity focus setting isn't a default setting (one might expect it to be at 1.0 but this isn't
the case for any of the S23 Ultra cameras I've tested).
This study shows the behaviour for the main x1 W camera as the manual focus is adjusted over a range
around the optimum value. The S23 Ultra was on a tripod and the same exposure settings were used
for all photos.
The photos were taken from 8:58 - 9:10 PM EDT Mar 20, 2024 with settings:
W x1 camera: Expert Raw Mode ISO-800 8sec WB 3400
The optimum setting for sharpest star images with the W x1 camera was 0.90 (center image). (Infinity focus settings
for my other S23 Ultra cameras were similarly measured to be W X3: 0.70 and Periscope X20: 0.62). It isn't known
what the manufacturing tolerance of the S23 Ultra infinity focus settings are.
Note that out of focus images actually look
brighter, probably because of light saturation on pixels for sharper focus.
The video below shows the trend for the 14 settings on the focus adjust slider between 1.0 and 0.80. Dial settings
are shown only for the start, optimim and end photos.
Each photo was taken twice for a total of 28 photos in the animation.
