Originally Posted by Athiril
we've tested the current 400 ISO colour films of the market.
Test method: real life photographs with an object contrast of only 1:4 (two stops).
Lenses: AI-S Nikkor 1,8/50 and Zeiss ZF 2/50. Both at f5,6.
With Nikon F6, MLU, Berlebach 3032 tripod, 1/250s, focus bracketing.
Provia 400X: 105 - 115 linepairs per millimeter
Portra 400 new: 80 - 100 lp/mm
Fuji Pro 400H: 90 - 105 lp/mm
(first value represents clear separated lines, second value the limit where still a difference in contrast can be seen).
Provia 400X clearly surpasses Portra 400 in resolution (and Pro 400H). And with contour sharpness as well.
Not surprising, because in most cases slides films deliver better detail rendition compared to colour negative films of the same speed. Especially at low and medium object contrasts.
ISO 100 films (same test method):
Ektar 100: 90 - 105 lp/mm
E100G, Elitechrome 100, Sensia 100, Provia 100F, Astia 100F: 120 - 135 lp/mm
Velvia 100 / 100F: 125 - 140 lp/mm
By the way, pushing Provia 400X: I have often done it and never seen a colour cast. Colours have always been accurate.