This is a continuation of testing of the following macro lenses :
- Sony 90mm f/2.8 FE Macro
- Leica 100mm f/2.8 Apo Macro-Elmarit-R
- Zeiss 100mm f/2 Makro-Planar ZF
- Nikon 105mm f/2.8 Micro-Nikkor G VR
- and, now, the Coastal Optical 60mm f/4 UV-VIS-IR
The test starts here:
A few have expressed some surprise at the performance of the Coastal 60/4 at f/4 and f/5.6, which has prompted me to rerun the tests at 1:10 (one tenth of life size) magnification.
Here are the LoCA results at f/4:
The vertical axis is MTF50, measured in cycles per picture height (cy/ph). The horizontal axis is camera position shift in cm (not mm, as was the case in the 1:2 tests). The points on the left side of the graph are with the camera farther away from the subject than the points on the right. I used a 500 um (0.5 mm) step size. The three raw channels are plotted.
The 1:2 results are here:
There is more LoCA at 1:10 than at 1:2 magnification, but the MTF50 numbers are quite a bit higher.
Here are the 1:10 results for f/5.6, f/8, and f/11:
And here are the focus shift results:
For reference, here are the focus shift results at 1:2:
Don’t forget that the horizontal scale is different: mm in the 1:2 graph and cm in the 1:10 graph.
Two things stand out. The lens is much sharper at 1:10, and the focus shift is in the opposite direction. Is there a magnification between 1:2 and 1:10 where there is hardly any focus shift? Probably, but I’m not going to take the time to go searching for it. Did I mention that these tests are labor-intensive?