Note: this video was focused by two synchronized motors linearly. So the result is inaccurate.
Sharpness test for Leica Elimarit R 135mm f2.8 and Kowa 8-Z on BMPCC4k.
@2.8 (wide open) is usable (sharpness is acceptable) from 2.5 meters distance.
@4.0 (1 stop close) is usable from 2.0 meters.
@5.6 (2 stop close) is usable from 1.5 meters (nearest).
Actually it depends on the taste of the project. Refer the following test movies for the taste.
side by side
Full resolution screengrabs
1.6, 2.0, 2.5, 3.0m
Metabones Speedbooster XL 0.64x
Leica Elmarit R 135mm f2.8 @2.8, @4.0, @5.6
Kowa 8-z 2x anamorphic
Shutter: 45, 90, 180
BRAW 4K DCI (4096 x 2160) 3:1
Crop factor: 1.22x ( = 1.9 x 0.64 )
Colored with Davinci Resolve 16 (contrast only)
Resolution: 4096 x 1716 DCI Scope 2.39
Video Codec: H.264
Audio: Main 1 (Stereo)
Audio Codec: Linear PCM