Si l'on en croit cette note d'Imaging Resource, les tests de résolution
des objectifs sont illusoires.
Si j'ai bien compris, les tests en Jpeg direct sont tributaires de
l'accentuation réalisée au sein du boîtier. Or de légères modifications
de cette accentuation ont des effets notables sur les résultats du
Donc les tests non personnalisés ne veulent pas dire grand chose.
Et si l'on fait du RAW, alors ces résultats seront tributaires des
choix faits (logiciel, réglages...)
Ceci explique peut-être les avis parfois divergents sur la qualité de
telle ou telle optique, ou même de telle association boîtier+optique...
Note: We don't feature SFR-based LW/PH resolution numbers more
prominently in our reviews (eg, outside the Imatest pages) because
we've found that they're *very* sensitive to minor differences in
in-camera image processing. Relatively small changes in the amount of
in-camera sharpening can have a large effect on the resulting
resolution numbers. Imatest attempts to compensate for this by
adjusting to a "standard" sharpening, but this approach can't
completely undo what happens inside the cameras, and so often gives
inconsistent results. Sometimes the "standardized" sharpening happens
to just match the shape of the edge profile with the in-camera
sharpening applied, and you'll get wildly high results. At other times,
it will tend to correct in the opposite direction. Unfortunately,
ignoring the in-camera sharpening entirely can result in even greater
discrepancies, particularly between models from different
manufacturers. Turning off sharpening in the camera may or may not
fully eliminate the sharpening, so simply turning off sharpening in the
camera JPEGs isn't a reliable solution. It also wouldn't be the way
most people shoot the cameras. We could process RAW files with no
sharpening (as shown below), but then that'd only suit the people
working primarily or exclusively from RAW, and would open another can
of worms as to what RAW converter was used, etc, etc.
The bottom line is that numbers for resolution only take you so far.
Detail handling and edge acuity are very complex issues; ones that
don't easily boil down to a single number. The best approach is to
simply look look at the broad array of standardized test shots we take
with each camera, to the point of downloading and printing them with
whatever processing you'd use if you owned the camera and shot with it.
See how the differences stack up for you visually, and make your
decision on that, rather than on abstract resolution numbers.