This is one in a series of posts on the Fujifilm GFX 100S. You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can use to get to all the posts in this series; just look for “GFX 100S”. Since it’s more about the lenses than the camera, I’m also tagging it with the other Fuji GFX tags.
In previous posts, I looked at the off-axis MTF50 and microcontrast of the Fuji zoom lenses. In this post, I’ll compare the contrast of those lenses
Here’s the test protocol:
- RRS carbon fiber legs
- C1 head
- 100, 150, and 200 mm focal length
- Target distance as per the table below, interpolated as required
- ISO 100
- Electronic shutter
- 10-second self timer
- f/5.6 through f/11 in whole-stop steps
- Exposure time set by camera in A mode
- Focus bracketing, step size 1, 120 to 60 exposures
- Initial focus well short of target
- Convert RAF to DNG using Adobe DNG Converter
- Extract raw mosaics with dcraw
- Extract slanted edge for each raw plane in a Matlab program the Jack Hogan originally wrote, and that I’ve been modifying for years.
- Analyze the slanted edges and produce MTF curves using MTF Mapper (great program; thanks, Frans)
- Fit curves to the MTF Mapper MTF50 values in Matlab
- Correct for systematic GFX focus bracketing inconsistencies
- Analyze and graph in Matlab
First in the center:
On the right edge, with the slanted edge in a radial orientation.
Also on the right edge, with the slanted edge tangentially oriented:
It is apparent that the 100-200/5.6 is not as sharp a lens as the other two.