Hi,
Here are the MTF curves of a a HR Digaron-S 100/4 and a Zeiss 100/2.0 Macro Planar. The Zeiss is a lens widely considered to be one of the best on 135.
Please note the following:
1) Zeiss curves are for 10, 20 and 40 lp/mm
2) HR Digaron curves are for 10, 20, 40 and 80 lp/mm
So you should compare the top three curves.
135 format stretches to about 21.5 mm, so you can ignore anything beyond 21.5 mm on the Digaron curve.
So MTF at 40 lp/mm varies between 70% and 60% on the Zeiss, which are very good values.
On the Rodenstock lens the corresponding values are 85%-80%, so the Rodenstock is probably better if judged from these curves.
On the other hand, the Zeiss data are measured while the Rodenstock data is probably taken from lens design calculations, also I don't know if it is for white or monochrome light.
Keep in mind that lenses have other properties than sharpness, the way out of focus parts of the images are rendered is also important. The area of a picture in absolute focus may be very thin!I also include MTF curves for the Coastal Optics 60/4 Macro that Lloyd Chambers (Diglloyd) considers to be the best lens MTF 40 LP/mm seems to be just below 0.8 at f/5.6. This lenses looses sharpness at f/8. I have a hunch that the Rodenstock data is a bit optimistic. I would expect a truly excellent lens to be diffraction limited at f/5.6 or f/4.
Best regards
Erik
I settle with the assumption that it is an HR lens, and the HM is just a typo, since there does not seem to be such a lens.
One sentence in the above link seems to show that I had turned the problem upside down:
"But the HR lens line's abilities go beyond even the extreme high definition of Rodenstock's other excellent optics, providing resolution comparable to that of the finest prime 35mm format lenses."
I thought digital lenses, also non-HR, were BETTER than even good 35 mm lenses.
Thanks for the link! This new enlightenment makes this thread on the sharpest 35 mm lenses even more interesting...