The Schneider regular SA f5.6 has an identical spec IC to the Nikkor f8 and f4.5 at 235mm. The 90 XL spec is 24mm larger at 259. The regular Schneider SA f8 90 is specd at 216, 19mm less. Nikon specs their f8 lens at f22, while they spec their f4.5 lens at f16 -- a significant difference and why they spec the same total (smaller apertures generate larger IC's).
Now note you need 154mm IC to fully cover the 4x5 frame. So with the regular Schneider f8 SA, I can shift a total of (216-154)/2 or 31mm; the Nikkor can theoretically go (235-154)/2 or 40mm -- a 9mm difference if the spec isn't overly optimistic. At the end of the day, I never shifted more than maybe 15mm tops with my 90, so never even came close to running out of IC on my Schneider, but YMMV... Personally, if I knew I was going to need gobs of shift, I'd consider the XL to insure I never ran out! (Actually, I'd buy the 72 XL instead if I needed that kind of movement, but that's another story .) Seriously now, the 90 XL will generously cover 5x7 with about 30mm of rise capability, and 5x7 is where this particular set of lenses is going to be challenged on IC, not at 4x5...
Cheers,
Now note you need 154mm IC to fully cover the 4x5 frame. So with the regular Schneider f8 SA, I can shift a total of (216-154)/2 or 31mm; the Nikkor can theoretically go (235-154)/2 or 40mm -- a 9mm difference if the spec isn't overly optimistic. At the end of the day, I never shifted more than maybe 15mm tops with my 90, so never even came close to running out of IC on my Schneider, but YMMV... Personally, if I knew I was going to need gobs of shift, I'd consider the XL to insure I never ran out! (Actually, I'd buy the 72 XL instead if I needed that kind of movement, but that's another story .) Seriously now, the 90 XL will generously cover 5x7 with about 30mm of rise capability, and 5x7 is where this particular set of lenses is going to be challenged on IC, not at 4x5...
Cheers,