The most satisfying answer sounds very definitive: the wider lenses generally do not, the longer lenses generally do-ish.
But I'm going to give you a far less satisfying but far more useful answer: it depends.
Like most "how do X lenses perform" questions it depends on:
- how you're using them
- how you're judging
- what your comparing it against
- which samples you test
How you're using them:Aperture is the most obvious example here. A lot of lenses that are very mediocre wide open perform brilliantly when shooting at f/11. If you're a landscape shooter who always shoots at f/11 then that is the use-case that matters to you and performance wide open is really not important. In contrast if you're a portrait shooter that prefers the wide open look then performance at f/11 is irrelevant and performance wide-open is all that matters. But other things matter as well. While not strictly "lens performance" if you prefer to or must hand hold but the results hand-held are not sharp enough for your needs then the "lens performance" is moot. If you can't focus the system accurately then the lens performance is moot. etc etc The real world is different and more complex than a single isolated component tested in a lab.
How you're judging:Screen? Print? At what size? With an 80mp back your native print size at 240ppi is 43" by 32". If you print, for example, 16x20" you may find that issues that are obvious "on screen" (viewed at 100%) are completely meaningless in the print. If you're printing at 60x80" and walking up to the print you'll notice every little thing. Channeling a philosophy professor: if a slight softness exists but you never see it, is it truly there?
Also what criteria matter to you? The landscape shooter is going to notice and care about sharpness in the corners while the portrait shooter may find that it doesn't matter, or in fact that they prefer a slightly soft corner! How much does chromatic aberration (CA) matter to you? I've worked with shooters that don't seem bothered even by massive CA and shooters that can't tolerate even a whiff of it.
What you're comparing againstWe run into this every day at the office. Two customers walk in the door and try a specific lens (e.g. the Hassy 40). One is coming from Canon and the other is coming from Tech Cameras with Rodenstock HR lenses. The results of the test are the same, and one is hugely impressed and the other is disappointed.
In other words, everything is relative. The Mamiya 45D was a perfectly fine lens, and when you were comparing it to the Mamiya 35 it held up quite well and many were pleased with it. When you compare it against the new
Schneider 45LS Blue Ring or a Rodenstock 40HR the flaws of the Mamiya 45D become hugely magnified by the comparison.
Which Samples You TestTop quality control specs, even for Zeiss, were nowhere near what they are today in a modern line like the
Schneider LS Blue Ring. Variation from one copy of a specific film-era Hassy lens model to another could be significant the day they were made, and only vary more thereafter with use/wear/tear.
Bottom LineThe bottom line is you should go TRY the back with your system. Fortunately this isn't hard. Most Phase One dealers would be glad to arrange testing for you by any number of means (in their studio, in yours, in person, via shipment, rental toward purchase, whatever... I can't speak for other dealers specific policies other than, broadly, they will be eager to help). That is certainly the case for DT; we have
Phase One Demo Facilities in NYC and LA and ship anywhere in the country. Put the back on YOUR body, put YOUR lenses on it, and go shoot what YOU shoot, and judge how YOU shoot. If you like the results, buy it, and if not, don't.
There is simply no substitute for your own testing.
