Hi,
The guy just spent a few tens of thousand dollars on an system that is supposed to deliver 100 MP of detail, having a focusing system that is supposed to compensate for camera rotation.
We don't have 100 MP on mirrorless yet, although Phase already uses the new sensor for aerial imaging.
The existing mirrorless systems allow you to select the focusing point freely, so there is no need for True Focus.
One interesting issue that was quite obvious in Neil's images that the 150 mm lens is not well corrected for axial chroma. The straight image with True Focus activated has green fringing:
The next image with True Focus engaged and a camera rotation has magenta fringing:
After that it seems that Neil tried magnified live view and got no fringing:
These samples show that the HC 150 lens is not well corrected for axial chroma and that focusing may not be accurate enough to avoid axial chroma.
An interesting question may be: Would Neil achieved a better image with a 50MP camera like the X1D or the GFX?
Jim Kasson has run a lot of tests on his GFX lenses and it seems that they are very well corrected. My guess would be that X1D lenses perform at the same level. It may be that GFX lenses have more sample variation than X1D lenses, but it seems that all lenses Jim got were pretty good.
It also seems that most lenses are pretty decent. Obviously, no lens can exceed the design criteria. Jim Kasson has developed a lens screening method. I put some of my lenses trough it and all three were pretty OK.
https://blog.kasson.com/lens-screening-testing/examples/good-100mm-lens-on-p1-p45/https://blog.kasson.com/lens-screening-testing/examples/ok-60mm-lens-on-phase-one-p45/The third lens was the Sigma 24-105/4 Art at three different focal lengths. I don't think that Jim Kasson has a public link to that lens, but he felt it was quite OK.
To sum it up a bit...
- I don't think that old film era lens designs are a good match for today's digital sensors. They may deliver good results, but axial chroma is probably not corrected well enough.
- Modern focusing systems allow for critical focus anywhere over the frame. Older systems have a single focus point and using that focus point for of axis focusing does induce an error. Hasselblad has developed a complex solution around the issue with "True Focus".
- Modern, EVF based, systems use the sensor itself for focusing. A simple and good solution.
- Both the X1D and the GFX are designed around the sensor. In all probability they are designed around 2018 sensor technology /li]
I would argue that it makes a lot of sense for newcomers to MFD to spend their money on systems that are designed for 2018 sensor technology than on systems designed for film around the turn of centuries.
Best regards
Erik
The OP in your link was shooting a portrait with a large 100MP medium format camera, and a wide open 150mm lens, with no experience of doing so. With all respect, I'm not surprised he had difficulty in getting sharp pictures.