Hi Henrik -
I agree - there is no reason to cast older lenses in a negative light, there are many strong performers and good glass is good glass. The one area where newer lenses usually outperform is with respect to chromatic aberration, and of course high sync speeds with certain leaf shutters, etc.
But back to the Schneider 55mm and its wavy charts. We compared this lens against the Hasselblad 60mm/3.5 CB Lens. While they appear equally sharp (and equally focused) in the center, the edges are a different story. All 4 edges look equally similar wit each lens. Draw your own conclusions. Raws are available upon request.
This isn't to make any point about old vs new (I'm in favor of both - if they are both good), other than a response to the hand wringing over the charts.
Chris as I said before (to the "surprise" of some people) the 55mm was designed predominantly as a fast portrait lens for relative close distances. This is the manufacturer's description (the same one I happen to work for...): Minimal distortion wide angle design, provides a normal look, great for editorial portraits and on location lifestyle photography
From the Phase One website:
55mm LS f/2.8
A preferred choice for on location fashion photographers using fill-in flash.
With its extreme fast flash sync capabilities this lens makes it easy to balance flash and daylight and let's you create stunning images.
Regarding the wavy MTF chart with a really deep dip and then recovery at the edges.. well edge resolution is OK, it's more of an issue in the ring that the deep dip in the MTF graph
Here is pretty much where the ring falls. This is an approximation
based on the graphs. Not intended to be an definative argument, but to illustrate the issue
of a "roller coaster" MTF curve. Something to look for when test the lens and comparing to the far less expensive alternatives.
Full frame sensor such as iq180 or p65+
There are plenty of compositions where important features will fall into this lower sharpness ring.
Also regarding the editorial and lifestyle (fashion) photography attribution lets see where this falls in a magazine double page:
Full frame with a two 5:4 magazine pages side by side crop.
Here one can see that there is a significant area that falls into the deep dip of the MTF chart.
It's actually even more of a composition issue if you take into account the gutter in between the two
pages in the magazine.
Brown area indicated the gutter in the center of the opened up magazine.
Taking into account the gutter ones compositions tend to move more to the left for the left page and more to the right for the right page.
This increases the likely hood of important features being in the "deep dip"
With a crop sensor 33x44 it's less of an issue.
Full frame with 33x44 crop.
Fall off at the very corners is quite different from falloff nearer the center and then contrasted with sharper corners.
Lower sharpness areas are more apparent when they have higher sharpness areas on both sides.
This is hardly what one should expect from a $ 4,290 lens with a Schneider logo on the barrel.
Now that said images can be quite pleasing even with quite strong sharpness falloff, even dramatic falloff can be quite stylish
however I think one would prefer to blur in post rather than be stuck with it.